Categories
Greenhouse News

Capsicums

Fruit per m2 v light and temperature (part 2)

 

In the last edition of Grower2Grower I asked “if we have less fruit per m2 how much more speed/temperature can we gift the plant in late Autumn/Winter?”  I believe there is an answer but since I am not a computer, and we don’t have the ‘perfect’ controls, the conclusion we make as growers is always going to be subjective.  If I flip my question on its head, I would ask: at what temperatures, high or low will cause negative impacts on the plant’s productivity?  Low temperatures will both slow production and potentially have detrimental health impacts on plants.  High temperatures in relation to high fruit load and low light sum will also be counterproductive.  

 

Capsicums:

I want to start with Capsicums, mainly because millions of young plants have either just been planted or are soon to be planted.  Capsicums thrive in warm temperatures and are light sensitive. They are generally planted from April-July, with some smaller amounts planted outside of that window.   I am not a capsicum specialist but have always been fascinated with the initial growth and first fruit set kept for harvesting by the grower.  I have been taught that this plays a very important role in balancing a capsicum plant, which may determine the balance of the crop for the entire season.   I am not sure how all growers determine which of their first flowers they will keep for their first set, but I believe there to be multiple factors which are used for consideration.  Unlike tomatoes and cucumbers, capsicums are like watching a rather large bus go around a corner, things happen very slowly so if you make a mistake it takes longer to turn the bus around.

The first two leaves from each split is where the first fruits may be kept and encouraged to grow.  I have even seen some growers leave the crown fruit or the flower at the split, but more often than not it is removed.  In countries that plant in very low winter light levels they may wait until the third and fourth leaf, after the split, before they attempt to set fruit.  This demonstrates how every environment is different and how you must adapt your growing conditions. 

If you have been able to set the two flowers on both the 1st and 2nd leaf, after the split on each head, then these four-fruit become key for balancing the crop.  I was advised that you should sacrifice one fruit, when it was golf ball sized, on the less vigorous stem (if you are a two headed system) and pick the first capsicum as a green on the corresponding stem, you can then leave the next two capsicums to change colour if that’s what you are picking, (Growers picking green will probably have a different fruit loading method). The significance is so you don’t overload the plant in low light and it still has the ability to set new fruit on the next leaf nodes that flowers are kept on (keep in generative mode). Crops that have a large first set with too many fruit per m2 followed by low light will possibly have fruit abortion on the leaf nodes they hoped to be there next picking set, therefore unbalancing the crop from a generative phase back to a vegetative phase.   This can cause a delay in harvesting and a rather large loss of earnings. 

With light, the determining factor, and temperature the driver, it is important at a young stage of a capsicum plants development that you are not cautious but realistic with your fruit set per m2.  If you keep less fruit you could potentially run with a higher temperature and if you come into poor weather you have the ability to pull back on temperature, allowing the plant to hold onto the second set.  If you do have good weather you can potentially gift more temperature and build speed into the plant. 

Please feel free to let me know how you go about setting your capsicums at this time of year and the different factors that are involved for your growing operation.  Seed companies are most welcome to provide feedback.  Let’s learn together.

 

 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Greenhouse News

Air Movement and Moisture Distribution

Horizontal or vertical fans and air tubes, what are the experts suggesting

 

This article continues a theme from two weeks ago looking at the role air movement has in a greenhouse.  Below, is a very brief summation I have made in regards to fans and horizontal air tubes, from a book I am currently reading.

One scenario I came across last year was the difference in temperature and condensation from the top of the greenhouse to the floor once the crop was mature.  Shading from the plants had created a climate at the lower level that was cold and a fungal breeding ground.  I was interested to understand how more air flow at the lower level would be beneficial for a crop’s performance considering the property had heating pipes and a grow pipe.  As I understand the introduction of air tube, under the gutter, allowed the warmer air from the top of the greenhouse to be pulled back down and forced into the bottom of the crop.  The potential negative impact for high wire crops is the evaporation in the lower leaf area are stimulated so much that the water provided by the roots is consumed by the lower leaves before it reaches the top of the plant.  Possibly as a result, under intense radiation during the day, the top of the plant will struggle to transpire sufficiently to keep itself cool.   It certainly has merit during the night to keep the lower part of the plant dry but the effect on RH at different levels needs to be a careful consideration if you are thinking of using horizontal air tubes. 

Horizontal fans have been used for years to help create air flow in greenhouses.  Many growers, due to fear of spreading fungal spores, often don’t use their horizontal fans.  Basically, air blown over a long distance could actually absorb moisture on the way.  Potential cold pockets may form and this may result in perfect areas for botrytis to establish.  So, it is understandable why growers, myself included, are weary of using horizontal fans. However, I think the reason is not because spores are blown around but that we are actually creating, cold, high humidity areas.   This makes sense, if only I knew this 20 years ago.  Horizontal fans will create air movement but mainly above the crop, so this still doesn’t solve or create an active climate amongst the crop. 

 

When it is explained it makes sense that vertical fans have an advantage over horizontal fans and tubes.  The positive features of vertical air movement include:

 

1, More air movement in between the plants

2, Moisture is moved from the crop to the greenhouse roof via the shortest possible route

3, Fewer cold or hot spots through the greenhouse

4, A better vertical temperature profile

5, Heat from lamps is pushed downwards to the crop, so no or less additional heating capacity is required

6, If the air movement around a flower bud or plant tip Is more that 0.2m/sec, it will reduce the overheating caused by radiation of that plant part

7, The vertical distribution of CO2 can be improved.

 

If you would like the longer, more detailed version regarding air movement from using fans or horizontal tubes then I highly recommend you should read a book called Plant Empowerment, The Basic Principles.

 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Technical

Fruit load per m2 using temperature and available light (part 1)

Less fruit load more speed

 

This week’s articles, although different, follow a pattern.  It is an important time to start working on the little things that could vastly improve productive outcomes.  Fruit numbers m2, especially as we are heading towards May, is a very important topic of discussion.  For tomatoes, anything that is flowering and setting now will be not be harvested before we are well into the winter period.  Harvesting speed, for each different crop, will be dependent on inputs.   As growers, in general, will have different stem densities I feel it is probably best I tackle an article regarding fruit per m2. 

 

What got me thinking?

While walking through a standard, loose, round tomato crop, picking at truss 5-6, it was interesting to come across a plant that had a truss broken. There was only two trusses above where it was missing and four and a half below.  So not too far from the head, which is important to note as the fruit on that truss, on the other plants around it, were still small, so visually you think how could this small truss have consumed so much energy?  What was noticeable was the immensely larger fruit, which was on the lower trusses, compared to the plants that had not lost a truss.

When I first started using a consultant, as a grower, I was always instructed not to remove a truss as this would throw out of kilter, the balance of the plant.  I still agree with that; I think the total removal of a truss becomes a necessity because of a plant health issue or incorrect management decision to overload the plant, which could in turn have caused a health issue.  Never the less, and whatever the reason this particular plant poses some questions.

 

What is the correct fruit numbers per m2?

There will be many theories answering this question but with detailed crop registration, over the years, most growers have been able to gradually come up with numbers that have been workable.   We have an agreed number of fruit m2 in our heads and using this number, and calculating the predicted available light will then come up with advised temperatures to match the fruit numbers.  The problem with these estimates is that it is not a perfect science, no algorithms (yet), just years of learning and predicting.  What I have come to realise is that less fruit, and harder pruning, could potentially yield slightly less production but it will realise fruit size that will reach premium price. 

 

Increased temperature with lower fruit per m2?

The most important question I have is ‘if we have less fruit per m2 how much more speed/temperature can we gift the plant in late Autumn/Winter?’  If, all of the plants used in my example, had a truss removed then there would’ve been a need for a much higher twenty-four hour temperature to ‘speed up’ the ripening process.  The fruit were becoming too big, and soon would be in a lower price bracket, so the only way to pick this fruit off faster would be to increase temperature and therefore increase speed.  With winter approaching we look to drop our twenty-four-hour temperature, as we don’t have the light to grow with speed, but if we looked at further reducing our fruit load, we would, in theory, be able to grow with a higher twenty-four-hour temperature. If you are energy conscious then please don’t worry because I believe this could be achieved using increasing day temperature on light, or a day boost.  There are also plant health advantages, if you have warmer pipe temperatures for example. 

 

Suggesting fruit loads per m2 comes from experience, but I believe new technology and evolution will one day have a computer algorithm spurt out exactly what we need but until then we must use our crop data to make the most informed decision possible.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

 

Categories
Greenhouse News

Public holidays equal two short working weeks

How do you catch up on your plant work?

 

This year’s Easter period was particularly difficult. If Easter Friday & Easter Monday weren’t hard enough we had Anzac Day in the same week.  The only option, for a lot of growers, was to request their staff worked at the weekends.  Plants don’t stop growing or producing because there is a public holiday.  This is particularly hard on staff who were requested by necessity to work on the weekends only to have three random days off, they possibly did not want during the week.  I know how much of a challenge this is.

In a perfect world staff would all be able to enjoy the long Easter weekend break.  It just is not feasible, for example, it will be impossible for cucumber growers during their harvesting phase to go five days without picking. 

So, for now the only option is to carry out those tasks on the weekends, on days which are not public holidays.  The staff costs, on public holidays, is excessive.  Unfortunately, growers cannot add a surcharge to the fruit for plant work completed on public holidays.

 

Catching up:

The weather is still ok and growth rates are still good, so if you have got behind in your plant work then your focus will be on catching up.  When you are behind in your plant work, very quickly there is a ‘knock on’ effect.  The first thing that will be neglected is pest populations.  So often, when the foot is taken off the throat, pest populations quickly increase.  This is exactly what I have seen over the past two weeks.  Whitefly, in particular, has increased and going into the winter this is the time it really should be under control.  If you have been able to control your numbers, then for tomato and cucumber growers, it is an ideal time to start re-introducing IPM.  TPP numbers, hopefully, are negligible, therefore you can feel more comfortable moving to IPM programmes. However, if Whitefly numbers are too high then you might have a battle on your hands for the duration. 

Having your focus diverted to ‘catching up’ with the plant work may also cause a reduction on the precision of a plant’s growth.   Being behind with tasks, such as pruning and leaf removal, can knock the balance of the plant, which, at this time of the year, is crucial as every bit of light counts.   

 

Big vs. Small:

Growers, who are family operations, will have been able to keep up with their normal work load, as they would have taken up the slack and worked on those public holidays, if their staff were away.  Bigger growers would have had no choice but to ask staff to work on the weekends, it is not what I believe they would like but it is just a reality. 

 

Being Prepared:

Being prepared in advance for public holidays is all well in good, but even if all your work is up to date, the plant is still going to continue to grow.  It would be like milking Daisy the cow a bit harder on Thursday and asking “hey daisy you have the weekend off, and please don’t produce any milk until Tuesday!”.

 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

Categories
Category

Building in Mud

New projects could face challenges

 

Building a greenhouse in Autumn will be tricky for both the grower and greenhouse builders. (Unless by some minor miracle), a build at this time of the year will possibly run into issues with the weather during the construction and invariably mud.  I have been part of a build that had issues with mud in the months of May and June.  The mud was deep enough to lose sight of your boots every 10 to 20 steps you took.  The slowdown in productivity is huge and may add large amounts of costs and stress for growers.  Unfortunately, greenhouse builders cannot be everywhere at once, so building during ‘ideal’ periods of the year is not always possible.

For the builders themselves, they have to be extra careful when constructing a greenhouse in poor weather conditions.  The potential increase risk of accidents will naturally mean the builders will have to be vigilant to ensure their own safety and to protect the greenhouse from damage.  

Once the builders have completed the task of building the greenhouse the internal fit out will begin.  When dried, which may take a long period of time in the winter, the ground may need to be re-levelled.  When mud or clay dries it is not easy to get the soil to a fine, sand like, particle size, you end up with lumps and bumps that somehow need to be broken up.  Depending on what type of system you have, for example hanging gutters, some growers might not think it is important to have perfectly level floors.  Most greenhouses will have internal drainage systems in the ground between each bay, so it is still important and should be as accurate as possible to remove any potential ponding areas.  A dry greenhouse is a happy greenhouse. 

Time equals money and this is when corners can be cut on the internal layout.  It is good to have a dead line for when the crop needs to be planted as this is motivation but there are more chance of mistakes and imperfections when deadlines are set in concrete.  Crop cycles are very important and therefore planting dates. However, I would consider talking with your nursery, check availability and only confirm your order when you are confident you will be ready for planting.  This can really take the pressure off.  

The internal layout of the greenhouse is just as important as the structure.  You only have one first chance to get it right, fixing and retrofitting are an option but would incur unnecessary costs in the future.

 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

 

Categories
Technical

Wind-side and lee-side venting

Is this important?

 

As a grower and advisor, I am continually learning.  The more I discover about precision growing, long term practices are brought into question.   Having open discussions with growers, in regards to these new theories, is something I believe is constructive.   Over the next few G2G editions I want to look at some of the theories, from a grower’s perspective, and how, if at all, they can be implemented into our growing situations.  Your feedback and questions are most welcome.

I have believed, for a very long time, the importance of everything being as even as possible in a greenhouse.  Even temperature, even irrigation, even transpiration throughout a crop.  A bug bear for me has been greenhouses built with too much slope.  Falls have been necessary to efficiently drain the rain away quickly, but never the less it equates to a slope in your greenhouse. This will lead to uneven air temperatures with hot air rising to the higher end and cooler temperatures at the lower end of the greenhouse.  The distance and degree of the slope, leads to variation of transpiration rates within different areas of different structures.  The cost to production is not hard to visually prove.  Greenhouse companies have had little choice and have had to build with falls.  However, over the past few years the engineering of greenhouses has improved so much that things like posts are being used as downpipes, so the need for such large falls are being negated.

 

Wind side venting:

A few moons ago, when I was starting out in my growing career, I was influenced to use lee-side venting over wind side venting for many reasons, which were valid and logical theories at that time.    As new technology, and new scientific information, becomes available, I question the practices I implemented.  I think this is one of the great things about growing in a controlled environment, how every detail, for potential gain, is looked at by some very smart people.   For myself, I need to understand these theories and how to (or not) best apply them to each and every different greenhouse structure I advise to.  

As a young grower, I used leeside venting almost by default.  It was advised and built into the computer system!  It was always a great way to maintain higher humidity levels in a greenhouse when I wanted.  I still see the benefits for cucumber crops that are struggling and how a reduced air movement (depending on outside windspeed) can help protect crops.  However, in modern tall greenhouses the effects of this are less important, as the top of the plant is a long way from the vents. 

What I did not take into account was the actual air movement, when using leeside vents only, and the effect on moisture distribution within the greenhouse. Thinking back to my greenhouse, it starts to make sense why the west side of the house always had slightly more vegetative plants, it wasn’t necessarily air temperature but too higher moisture or humidity levels.  As I understand now, by only using leeside venting air is pulled/sucked mainly into the greenhouse via the vents closer to the east side of the greenhouse.  The movement of moisture and heat then (basically) moves horizontally back to the west end of the house before rising and exiting the greenhouse.  This definitely had the effect of trapping humidity or moisture but all I was doing was creating an uneven climate and air flow, including an unevenness in natural C02 distribution.   In complete contrast if I was using only wind side venting the opposite would have occurred with cold air entering the west side and moisture exiting on the east side of the greenhouse. 

It makes relative sense then that if both lee side and wind side vents are opened evenly air movement and moisture exchange will be more even between each bay.  It would help ambient C02 being distributed evenly.   Now that greenhouses are generally built much higher, than in the past, the gap between the top of the plant and the vent are further apart, therefore the effect from ‘squeezing’ wind-side vents to reduce excessive movement in plants should be less of an issue then for lower structures.

A question I have is ‘At what wind speed should we be using our influences to control the opening of the wind side vent?’  For example if the wind speed is 10ms, it is very warm and to control the environment we need 60% venting capacity, should the wind-side and lee-side both be at 30% open or should the wind-side be at 10% and the leeside 50%?  So, what are the parameters or target figures we should be aiming for? 

I will be suggesting to growers that they think about using wind side venting to help create better air flow.  It does make sense, however, as I demonstrated by my question above I can’t give the perfect formula when I still have many questions that require answers.

In the next G2G edition I will write about the role of fans for air distribution and moisture distribution. Horizontal or Vertical, what are the experts suggesting?

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

 

Categories
Consumables/Hygiene

Rodent numbers high

Rats, Mice and even Rabbits damaging plants and fruit

 

No, I am not talking about politicians or politicians swallowing rats!  I am actually writing mainly about rats.  I for one do not like rats, I apologise to all rat lovers but growing food and rats don’t mix.   I have been in disbelief at how many rodents I have encountered recently.  Many companies will be doing a roaring trade selling rat bait.   Just yesterday (Thursday 17th) two rats almost ran over my feet while visiting a greenhouse.  Two weeks ago, at another property, a rat taunted me and stared me down!  I have heard of a cucumber crop that had rats climbing up the stems and biting into every stem fruit!

I will never forget many years ago, walking through my greenhouse, watching a mouse being chased by a rat!  I had never seen anything like it.  Rats cause large amounts of damage including eating fruit, chewing through wires and blocking up drains.  The only way to temporarily eradicate rats, and I say temporarily as they always come back, was to set bait stations, snap traps and live traps.  Live traps were particularly difficult because you then have to dispose of the rat, but these worked much better than the snap traps with a high percentage catch rate.  During the 1990’s we temporarily adopted my sisters’ cats, for several years, while she was on her overseas experience.  While we had the cats, I can’t recall ever seeing a rat or mouse in or around the greenhouse it was only when they left, I started having issues with rodents again.

A few days ago I witnessed them live in action, courtesy of a live camera I am connected to with one of the growers I advise to. I decided to have a nosey in the evening, unbelievably the first thing I saw staring back at me was a great big rat.   When I rotated the camera, it must’ve spooked the rat and it ran off.   I messaged the grower and the next day he purchased bait.  One option is to purchase the donut type bait that you thread steel wire through and secure it around posts. (cover photo) Rats also like to feed in pipes, I would thread wire through the pipe with the bait to make sure the bait could not be carried back to the rat’s den.  It is important the rats eat the bait and don’t carry it for storage otherwise they won’t eat it straight away. 

Baiting is probably the best option to supress rats.  I live by a small native area and I regularly bait the boundary of my property.  The reason I don’t have a cat is the bird population in the reserve. However, I do believe that not having a cat does mean I will be forever having issues controlling rodents. 

It is hard to put a figure on how much rats cost growers but be assured it will most likely be more if you don’t do anything about them.  They are very destructive and if left alone will multiply quickly.  Setting up baiting stations is a good option.  Doing it correctly is also important to ensure effective control.

 

Believe it or not the top of this cucumber plant was eaten by a sneaky rabbit that got into the greenhouse!

 

Tying the bait up will force the rodent to eat at the source.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

Categories
Greenhouse News

Grower Field Day and Workshop

“Growers are some of the best scientists”

 

On Wednesday 20th March a Grower Field Day was held at Anthony and Angela Tringham’s (The Curious Croppers) greenhouse property in Clevedon, South Auckland.  The field day provided an update and summary of two separate projects undertaken, to date, one by the Sustainable Farming Fund (SFF) “Tamarixia release and monitoring” project that is being conducted by PFR and managed by the VR&I board. Its project team and industry co-funding comes from Tomatoes NZ, Vegetables, Potatoes NZ, tamarillos and Watties for processed tomato growers. It is not specific to indoor crops – it is more focused on developing a colony, and looking at how to establish Tamarixia outdoors. It developed from the application to EPA to import Tamarixia, which was funded by those same groups (except SFF) and approved in June 2016.  . The second project is with the Bio-protection Centre at Lincoln. It is co-funded with an AGMARDT grant, TomatoesNZ and Vegetables NZ.  It is looking specifically at biocontrol agents for greenhouse use. So far it has focused on the Tamarixia and shelter plant (buckwheat) work.  The field day took place at the Tringham’s as small numbers of Tamarixia were released near their property last year.

There was a very informative presentation from Dr Shola Olaniya of Lincoln University.  Dr Olaniya has been closely involved with Tamarixia triozae scientific trials over the past few years.  He presented some of his initial findings from several trials.  He was very keen to engage with growers and said that “Growers are some of the best Scientists”.  This cooperation is essential if growers are serious about finding natural biological solutions to controlling pests, such as TPP, and even possibly changing farming systems.

If you wish to read more click on the following links:

 

https://www.tomatoesnz.co.nz/hot-topics/biocontrol-research/

Https://potatoesnz.co.nz/mdocs-posts/tamarixia-triozae_survey-guide/

 

As part of the afternoon we were invited on a tour of Anthony and Angela’s property.  One thing I was intrigued with during our walk of the property was the lack of pest insects in the surrounding flowers, grass and weeds.  Anthony and Angela are using their unique location, which is surrounded by grazing agriculture rather than intensive outdoor horticulture, to let their vegetation grow naturally.  The intention behind this is to create a bio diverse environment where “good bugs” can thrive.

Now I am no scientist, but I am not blind either.   What I observed, amongst the naturally growing canopy, were several flower species, long grass, weeds such as nightshade including tomato plants, which actually had lovely fruit on them.  Keeping in mind we have had a very warm summer perfect for insect pests, so why couldn’t I find any.   On all of the “wild” tomato plants I overturned I could not even see one whitefly or one whitefly egg. 

My advice is still for growers keep grass low and vegetation in close proximity to a greenhouse to a minimum, but if the correct balance of natural vegetation is planted that creates a thriving habitat for good insects, then I see no reason why this type of IPM would not add extra protection from unwanted pests entering greenhouses.  Not all, but a certain percentage of TPP carry a bacterial pathogen Candidatus Liberibacter solanacearum (Lso), and for greenhouse growers who have species which can be infected by this bacterial pathogen, there is rightfully a zero tolerance for TPP.  The hardest thing with TPP is that growers don’t often see them because of the current insect control methods. However, we still see Candidatus infected plants.   The TPP could fly in or be blown in via vents, and as only one grower in NZ has insect screening small enough to stop TPP entering its greenhouse to my knowledge, then I suggest we seriously talk about exploring these other options.  Creating a natural vegetation barrier could be an option to preventing TPP populations growing in your immediate surroundings.  Understanding how TPP travel and migrate is important along with growing vegetation that TPP predators thrive and survive in.  Its food for thought.

 

There was a large turnout which indicates this is a seriously interesting issue for growers.  Together with industry partners I am sure we would all like to keep working for improved outcomes regarding supressing the negative impacts of TPP.

 

Many thanks to Angela and Anthony for opening up their home and hosting the Grower Field Day including a lovely spread for lunch.  Special mention to TomatoesNZ and Vegetables NZ for assisting in the organising of the event.

 

Outside were wonderful colourful patches of flowers including weeds.  No insect pests detected. 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

Categories
Consumables/Hygiene Technical

How do you know what you have lost if you never had it in the first place!

Truss Arching, how important is it?

 

It is the middle of autumn; day light savings has been and gone and with it the illusion we have extra light hours.  Days are shortening rapidly however, we still have nice weather and even up until the shortest day should still enjoy some lovely sunny periods, but without the light intensity.  Truss arching or supporting is an essential part of reaching potential production in the autumn and winter.  Tomato growers, growing large truss or loose cultivars (even cocktail types), who are not using some type of truss support are missing an opportunity to maximise the size of your fruit.

When you bend a hose pipe you restrict the flow of water, a similar outcome occurs when a truss of tomato’s kinks or bends.  There are several reasons why the truss will bend, including low light, weaker trusses, due to high fruit loads, the age of the plant and even lack of nutrition.   Light is the most important, you only need to look at the outside rows of greenhouse crops to understand this. 

To accurately quantify the increase in production, of using truss supports, is very easy.  You could trial it in one or two rows to see if it makes a difference to your growing operation.   Many tomato growers already use some form of truss support. 

One of the reasons I am writing this article now is that I feel some growers have started using truss supports too late.   I always used truss supports.  With the cultivar I grew it was very important to start from the 3rd truss setting.  I planted in late February or early March, and if the 3rd truss was not arched, you could bet that 50% of the trusses would bend.  It was definitely a characteristic of the cultivar I grew.  It was not until December, and the heads were nearly too pinched, that the arches no were no longer required. 

 

How to apply arches:

It is important to know when and how to apply the truss supports, especially the truss arches. 

When: As soon as the distance between the stem and the first flower of the truss allows you to slip on the arch.  The longer you wait the harder to apply and more chance of breaking.  This can be discouraging and make you ‘gun shy’.   The early morning period is more difficult than the afternoon as the trusses are a lot more prone to breaking early.  If you are able, I suggest carrying out this job after morning tea.  I advise combining truss arching with truss pruning.  If you are regular with arching you can put an arch on the highest truss and prune the one below you arched the previous week.  In the autumn and winter the truss set speed is variable between cultivars so timing is different between properties, but in general once a week.

How: It might seem straight forward to put a truss arch on but it is surprising how many times it is put on incorrectly.  It is worthwhile for someone to demonstrate to staff the correct way to place arches on a truss.  I could try and explain this in writing but I think it would be easier to travel to Africa and back on foot. 

In summary, how do you know what production you have missed out on if you never had that production in the first instance!  The only way is to conduct your own trials.  I thoroughly recommend supporting your trusses.  The returns should far out way the cost.

 

Cover photo showing how to correctly attach a truss arch. 

 

This photo clearly shows the bending/kink of the truss. 

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower

 

 

Categories
Irrigation/Substrates Supporting Services

Smart Alerts Help to Achieve Optimal Rootzone EC and WC

Growers utilise BumperCrop to guide their irrigation strategy

 
Studies show that effective root zone management can lead to up to a 10% increase in yield and improvement in fruit quality. Because of this, the adoption of smart technologies like real time substrate monitoring and alerting is expected to double in the next five years. Adoption is being led by Europe, especially the Netherlands. Historically the Dutch have been fast adopters of new technology which has made them world leaders in greenhouse production.
New Zealand growers aren't waiting to start benefiting from these new technologies. South Auckland cucumber grower Edward Lee actively seeks out new technology that helps him to run a more efficient and productive greenhouse. “To survive in this industry, you need to be as precise as possible.” His approach is paying off as his business continues to thrive.

Edward’s latest technology addition is BumperCrop’s real-time substrate monitoring and alerting solution. “Knowing the WC & EC trends of my slabs allows me to irrigate precisely and achieve stable levels.  More accuracy translates to greater yield and earning more from my crop”. 

Automated text-alerts remind Edward to keep his EC levels stable. Over the last two months he has received several high EC alerts that prompted him to act quickly to keep his rootzone in balance and prevent problems with his crop. “I need to provide just the right amount of EC to prevent root stress”. Having timely information allows Edward to make decisions around when to stop and start irrigation as well as the frequency and length of irrigation.

 

Edward has found viewing WC & EC data and alert thresholds levels easy with BumperCrop.  There is a handy Mobile App as well as a user-friendly website to view current substrate readings in relation to threshold targets. “I like being able to get readings on my phone wherever I am. This gives me confidence that my greenhouse is operating smoothly even when I am not there.”

 

WC, EC & Temperature Sensors installed in rockwool substrate at Edward’s Cucumber Greenhouse

 

Alerts can also be setup to guide growers to achieve consistent substrate water content levels. Consistency increases yield and these alerts can also be used to help with detecting unexpected and costly issues such as clogged emitters or a malfunctioning irrigation system.  “Being aware of and adapting to changes in WC & EC has been particularly critical over the past few past weeks as changes in the weather and daylight savings influence crops. “

 

 

Grant Fannin is another cucumber grower benefiting from smart substrate monitoring.  “I check my substrate trends regularly to ensure they are staying within optimal zone.  I’ve found the sensor data to be very reliable.”  Grant finds it to be more precise than weigh scales.  “I can see how my WC trends change over time as the plant grows and this is not distorted by other factors like the weight of the plant”.

Grant accesses the data transmitted by BumperCrop from his phone.

 

BumperCrop sensors are designed to work in different media including rock-wool and coco fibre substrates.  BumperCrop is a New Zealand based company that offers affordable smart greenhouse monitoring solutions.

 

Bumper crop is offering a free 21-day trial of their system to Grower2Grower readers.

 

For more information contact Adam Forbes:

adam@mybumpercrop.com

Ph: 027 3512 512

https:/mybumpercrop.com/