Tomato growing Guide

Tomato is a crop I have studied for years and get a lot of joy yielding high quality, tasty, and long lasting produce. They're incredibly easy and a few plants is enough to feed a family plus some more. For a crop they're profitable, provide good cash flow through most of the season, and there is huge demand whether it is for fresh produce, tinned or otherwise. This information is given in good faith and is not to be taken as literal advice since everyone has their own environments that they need to contend with which this article does not take into account. When using this information keep in mind your own circumstances and apply with due diligence.

Seeds and seedlings

If you're only planting a few tomatoes you can source your seeds or seedlings from any home hardware store or nursery, if you don't mind spending a few extra dollars and want to have what the farmers get, you can go to an agriculture retail outlet and see if they can get you a small tin of hybrid tomato seeds which will grow much more vigorously, have a disease resistance package and produce a lot more fruit. If you're a farmer, you're probably ordering already from a seedling factory but the thousands, I do recommend always having a few hundred tomatoes of a new variety to trial in your soil and climate to see if there is anything that may perform better than what you already have, some of the new varieties can provide really good returns on investment.

If you've gotten or going to buy seedlings the first thing you want to do is inspect them for diseases and pests, this is important because you don't want to be introducing pests or diseases onto your farm or garden, if there is any problems you want to be on top of it as soon as possible otherwise you maybe facing an up hill battle for the rest of the season. I good practice for growers that are in high disease and pest pressure situations is to spray the seedlings prior to planting, this way they use only a small amount of fungicide/insecticide and they can protect their whole crop before it's in the ground.

Transplant shock
If planting seeds you won't be facing this issue, however, if you're using seedlings then there is a good chance that your plants will be experiencing transplant shock, this is normal but means that they will need some extra care to ensure they're not left without much water and have good contact with the soil. You will likely experience them wilting but should not be too much cause for concern.

Trellising

If you're growing bush tomatoes then you will not need to trellis your tomato crop but if they're indeterminate tomatoes, this means they have a growing tip that does not stop branching and fruiting, you will get a big benefit by trellising your tomatoes. There are two main types of trellising, one is by stake and the other is a string trellising called lean and lower system.

Stake trellising
Stake trellising is the simpler and more commonly used in open field environments. A stake is used as the climbing frame for the tomato plant and as the tomato plant grows a runner, it is tied to the stake using a trellising rubber band, tape or string. Studies so far have shown that having two runners per tomato plant produces the greatest yield, one runner produces less fruit which are larger while three runners will lead to more fruit that are smaller. Once the tomato plant reaches the top of the stake that is 7 feet tall the growing point of the tomato plant is cut off but it is possible to have the plant continuing growing, the only issue is having no more trellising space. From one hectare containing 16,000 fresh produce tomatoes trellised with the stake system using two runners, you should expect a crop that lasts at least 6 months with a yield of up to 100T. However, that was achieved in heavy clay soil of Carnarvon that has ideal weather for the better half of a year.

Lean and lower string trellising
This practice is common in greenhouses due to the protection from the wind and the ability to influence the climate in the greenhouse through the year resulting in longer crop lifespans, sometimes up to 18 months. Often each plant will have two runners but instead of trellised to stakes the runners are trellised along a line of string and held in place by plastic clips that clamp onto the string and have two arms that surround the stem of the plant. Once the tomato runner has reached the trellising wire height limit, where the string is coiled up with a gear, more string is released from the gear to lower the runner down and then moved across horizontally to keep the string taught, this allows the tomato runners to keep growing endlessly unlike the stake trellising system.

Nutrition

A tomato crop's nutrition is critical to high yields of quality fruit that provides high nutritional value but also great flavor. It's not all about applying heaps of nitrogen to get the largest volume of tomatoes to be harvested, there are massive profit gains to be made by consistently providing high grade fruit. Growers who are capable of providing a consistent stream of high quality fruit will be targeted for business opportunities and will get the better prices.

Tomatoes like all plants require all the nutrients, if we assume that there are 16,000 tomato seedlings per hectare that will grow for five months and used for fresh produce, then when we can make a rough estimate of the nutritional demand of the crop as per below for each of the nutrients:

1. Nitrogen @ 150kg/Hectare
   As the crop grows the demand for nitrogen increases, it is important to know that too much nitrogen can cause the plant to delay flowering which results in a longer time before you begin harvesting, too much nitrogen can also cause the tomatoes to become hollow inside and the inside flesh to be watery, tomatoes like this look puffy from the outside. If you don't want to be monitoring the output of your nitrogen too frequently then I suggest you use slow release fertilizers which can take a lot of the pain away from fertilizer applications and their timing, especially if you're in clay soils. However, in deep sandy soils you may need to monitor the output of your fertilizer continually even with slow release fertilizers. I have achieved lower nitrogen rates and this was through the use of nitrogen fixing bacteria in clay soils, this allowed the grower to apply slow release fertilizers with the bacteria to use less fertilizer and give them more time to focus on other aspects of the farm.
   The thickness of the tomato stem 15cm down from the tip is also good indicator if you're applying too much or too little nitrogen, the diameter of the stem should be around 1cm thick, if it is thinner then there is not enough nitrogen, if it is thicker then you are applying too much nitrogen.
2. Phosphorous @ 40kg/Hectare
   An important nutrient for the beginning of the crop. Phosphorous in the soil is very immobile and can be helpful by supplementing through fertilizer inputs close to the roots of the plant. The crop will require phosphorous throughout it's life but usually will not need additionally applications. Using mycorrhizal fungi can enhance phosphorous uptake but needs to be done where the soil phosphorous concentration is around 50mg/kg of soil. There is a relationship found where the higher the concertation of phosphorous there is in the soil the less the plant will take advantage of the mycorrhizal fungi, this means you can save on phosphorous fertilizer to achieve lower phosphorous concentrations in your soil. I highly recommend doing soil and tissue analysis if you're going to attempt this strategy.
3. Potassium @ 150kg/Hectare
   Potassium can provide the plant with resilience against drought environments and heat waves. It is also responsible for high quality produce in high yield environments. Often potassium input is matched to that of nitrogen and sometimes can be applied at higher rates. The demand for potassium in the crop picks up 1 month after transplanting the crop and will be high throughout fruit development and ripening. A lack of potassium results in fruit that does not ripen evenly in color, often having spots of green and blotchy which can be confused with the tomato spotted wilt virus.
4. Calcium @ 170kg/Hectare
   If possible, calcium can be applied as lime over your soil, this will provide years of adequate calcium with no problems of a deficiency. In your soil analysis you want to achieve a calcium cation exchange capacity above 60%, this will allow your crop to have adequate access to calcium which is responsible for strong cell walls especially in the fruit, a deficiency of calcium can lead to blossom end rot. Blossom end rot occurs when there are stresses applied to the plant, this can be through pests, diseases, bad weather, heat waves, water logging, ect. Once these stresses overwhelm the plant the calcium from the blossom end of the fruit is transported back into the plant and the cell walls start to decay, giving you the blossom end rot. However, if you have an abundance of calcium in the soil, in the plant, or pre-emptively spray calcium onto your tomato crop prior to a stress event then you can significantly reduce the impact of blossom end rot on your crop.
5. Magnesium @ 60kg/Hectare
   Like Calcium, magnesium should be provided to the plant through the bulk composition of the soil. Magnesium should roughly represent between 8-18% of the cation exchange capacity in the soil. Magnesium can be found in dolomite and blended with lime if necessary. This can be useful when treating for acidic soils as well. Magnesium deficiency expresses itself on the oldest leaves by making the parts in between the veins go yellow while the veins remain green, this pattern looks like a tree on the leaves. Magnesium is important for the function of chlorophyll and can be the reason why the leaf tissue turns the green chlorophyll in the leaf tissue to yellow.
   Sometimes a magnesium deficiency can occur even though there is a lot of magnesium in the soil, this can be because there are antagonisms that exist with other nutrients. The best way to get around this is to apply magnesium as a foliar spray, there are magnesium chelate sprays available that can be mixed with a lot of fungicides and insecticides.
6. Sulfur @ 10kg/Hectare
   Sulfur is required in only small amounts, often sufficient quantities are applied because they're part of a compound with nitrogen or magnesium. I personally have never experienced a sulfur deficiency but can be expressed as poor, short growth. The signs will show up as light green/yellow in the youngest leaves and work its way down the plant. If you're trying to correct a sulfur deficiency this can be easily corrected using ammonium sulfate or iron/zinc/manganese/copper sulfate blend.
7. Boron
   Boron is critical for plant reproduction and needs to be considered in the fertilizer program. Boron is readily mobile and can leach through sandy soils. Often this is not a problem because it can be found in a lot of irrigation water but should not be relied upon unless you have tested your water for the nutrient content and tested this on a small area of tomatoes. Boron deficiency in tomato plants are expressed as brittle petioles and branches which can easily snap off, when severe the growing tips of the plant will die off.
8. Trace elements
   Zinc, iron, copper, and manganese are required in such small amounts, milligrams per kilogram per soil or sometimes parts per million. The deficiency symptoms for these trace elements are:
   Iron: Pale/white young leaves, working its way down the plant to the older leaves.
   Manganese: Similar to magnesium deficiency but in the youngest leaves, the veins of the leaf remain green but the tissue in between the veins in the leaf turn yellow.
   Copper: The leaves curl upwards and the plant appears stunted in growth. the plant becomes a pale green and can be confused with nitrogen deficiency due to lack of growth.
   Zinc: yellowing in the middle of the leaves occurring near the middle vein.
   Trace elements are not required in large amounts and a soil analysis is generally enough to verify if there is adequate amounts. Trace element sprays can be very beneficial to encourage growth and amend any deficiencies in the plant. As you can tell from where most of the trace element deficiency symptoms appear, on the youngest growth, these nutrients are not very mobile in the plant and so requires assistance when necessary.

Pests

1. Grubs
   Depending on where you live, there is no doubt that there are Caterpillars/grub nearby that are wanting to have a chunk of your crop. In Western Australia they are prolific, especially in the northern regions where there are an abundance of different moths including the infamous fall army worm and cluster caterpillar. There are luckily plenty of options to choose from to protect your crop, organic or otherwise, checkout the organic crop protection article for some options. Grubs have caused the greatest amount of loss for a pest that I have experienced in my career throughout all crops I have dealt with, if you see a lot flying around at night it is a good indicator that it is time to get prepared.
2. Mites
   Small and can be hard to find. Using a magnifying glass and looking on the underside of the leaf can be a great help. Depending on the mite you're looking for they will provide different tell tale signs and can be found in different locations. If I suspect two spotted mites then I look on the underside of the leaves for any web. If I suspect red legged earth mites then I get close to the ground and look for them crawling on the soil, if there are damaging numbers then you should easily spot a few if there hasn't been any rain in the last few hours. Mites can cause major losses to the crops potential, I have seen russet mites in particular halve the crop yield potential because the grower couldn't find them (russet mites are crazy small). It is important to keep on top of mites and usually peak a couple of months into the growing season.
3. Aphids
   I have personally not experienced major losses from aphids but I can imagine if left uncheck that yield losses will be proven possible. There are a lot of different aphids that can feed on tomatoes, the most common in WA being the green peach aphid, cotton aphid, and melon aphid. There has recently been an introduced pest called the Russian Wheat Aphid but I am yet to see them on tomato crops. Aphids are sucking pests and you will find them doing the most damage on the fresh growing parts and tips. They're slightly larger than mites and can be seen in groups. Young aphids are flightless while some of the adults have wings.

Diseases

1. Early Blight (Alternaria .S)
   Early blight is something you want to keep on top of early in the season, especially in seedlings. This disease will first appear on the leaves and sometimes stems of your tomato plants. The appearance can take on a bullseye shape/circles in a brown/black spot on the leaf. If left unchecked the disease will spread through the crop very quickly and will jump from paddock to paddock by up to 100m from personal experience and probably further. In severe cases the whole plant will have sudden death and can affect large parts of the crop. Fruit size will shrink and fruit discoloration can occur.
2. Powdery Mildew
   This disease looks like a white powder covering the leaves which is actually a fungal disease. This disease is responsible for covering foliage and causing leaves to turn yellow and defoliate. In severe infestations it will cause crop losses but can be controlled with appropriate products and timing, so long as the mildew does not have resistance.
3. Bacterial spot (Pseudomonas .S)
   Bacterial spot, sometimes call bacterial speck or blight but best referred to as Pseudomonas (sue-do-monas). Mostly appears on foliage as spots/specks covering the leaf. If left unattended will cause the stem to crack and infect the inside of the stem which can be seen by snapping the stem and seeing discoloration of the inside. Pseudomonas is easily treated with potassium bicarbonate as an organic option and there are plenty of chemical products available as well. It is important to monitor for Pseudomonas because it will spread quickly in the crop and between paddocks and can result in large losses, in severe cases complete crop destruction.
4. Fusarium wilt (Fusarium .o)
   A soil borne disease that is most likely already in your soil if you're cropping in Australia. For decades it can survive in the soil without any hosts and destroy crops once fruit production begins and environmental stresses occur. The appearance of fusarium on tomato plants is the yellowing of leaves before defoliating, in severe cases the entire plant will wilt and die off, providing no harvest. There can sometimes be a reddish brown color in the stems and roots of the plant when cut with a knife. Fusarium spreads most effectively via the air with its spores as well as infected seed and soil. There are seed treatments for potatoes but this is not registered for tomatoes, currently known (as of 2022). The best way to combat fusarium in the soil is to plant resistant varieties and ensure that the health of the crop is being met through good nutrition and protection from pests and diseases.

Virus

Tomato spotted wilt virus
Tomato spotted wilt virus is a tospovirus, one of 16 known world wide, and is currently in Australia affecting tomato crops. This virus is transmitted by thrips which are tiny insects that are a sucking pest of a lot of crops. The spotted wilt virus symptoms can appear as excessive black spots or specks on the leaves, yellow circles and mottling of the fruit, and mottling of the leaves. Unfortunately, once a plant has tomato spotted wilt virus (TSWV) the plant must be removed from the crop and disposed/burnt. This means the only way to avoid loss is to use preventative measures if you know that the virus is an issue in your region. Below is a quick list to reduce the chances of getting TSWV:

1. Practice good hygiene
   Ensure to remove or desiccate the crop once you have finished harvesting from it. If you leave old crops unattended you're allowing pests, diseases, and any viruses build up which can impact newly planted crops or next seasons crops as these pests, diseases, and viruses can be transferred to weeds in your area.
2. Practice good biosecurity
   Biosecurity is monitoring what comes onto and off your farm. It is important to know where your workers have been recently, where equipment has been and products. Thrips can very easily cling to the fine hairs of clothes and if they contain the TSWV virus and jump onto your crop then that can be enough to introduce the virus into your crop. Greenhouses have the benefit of being closed off mostly to the surrounding environment and then provide jumpsuits to visitors and workers to reduce the introduction of pests, diseases, and viruses.
3. remove infected material
   TSWV spreads slowly through crops and so if you find that a plant has TSWV you can remove that plant and continue cropping. This is because thrips need to be born on TSWV infected plants to be able to transmit the virus, they also need to feed onto the plant for a certain amount of time, roughly half an hour give or take. This provides growers with enough time to identify the virus and remove the plant, it is also a good time to get an agronomist in or a government officer to assist with going through your crop to identify and test other plants for the virus to ensure there are no more plants infected.
4. Using insecticides
   Since the thrip requires to feed on a plant for a certain amount of time before it can transfer the virus onto the plant, there is an option to spray your crop to act as an anti-feed to the pest. This has not been a proven through trial work with data to back but it is a theory that can have some benefit if there is reason to believe that virus pressure is high in the surrounding areas. There are plenty of translaminar insecticides to use and there are also oils available for organic growers to achieve a similar affect.
5. Use tolerant varieties
   There are tomato varieties that are resistant to the virus and are very successful so far (as of 2022), over time it is expected that the tolerance may be overcome by the virus. Tolerant varieties are a very good strategy that can successfully protect tomato yields from a TSWV outbreak in the region. If you know that TSWV occurs occasionally in the area it would be a wise move to ensure at least a portion of your crops are TSWV resistant.
6. Avoid green bridges
   Most of the time this is unavoidable but can be achieved. A green bridge when used in regards to pests, diseases, and viruses as a place where they can harbor during the off season. A green bridge can be another or old Solanaceae crop (tomato, capsicum, eggplant)  that harbors the pests, diseases and viruses into the next season. This is why removing old crops is so important as they can provide that green bridge into next years crops and make it an uphill battle. I have seen this wear out growers and impact on their mental health because it increases the work load tremendously as well as the stress to achieve decent yields. Weeds can also be a green bridge, deadly nightshade is a Solanaceae plant that can be harboring TSWV into the following crop. Chilies are also capable of harboring TSWV without expressing symptoms, I have been fooled by chilies once when tracking down TSWV, chilies can live for over a year making it the perfect harbor for TSWV.

With this guide I hope that you are now equipped with the knowledge of growing your very own delicious tomatoes or a crop that gives you satisfaction and a living. Tomatoes are a favorite crop of mine because they can be challenging but if done correctly and nurtured with good intention provide great satisfaction.

Happy Growing!

Trouble shooting

If you have any problems with your tomatoes send me a photo and a little description through to my email at batemanagronomyservices@gmail.com
I am interested to hear what issues growers may face in their own situations.