You have planned carefully so that you will be planting tomatoes after the last frost, but there’s always the possibility of a rogue cold snap. Frost will kill tomatoes, so you will want to be prepared ahead of time in case you should need to act.
The simplest manner of frost protection for tomatoes growing is a cold frame. At its most simple, it is just some wooden stakes wrapped with a plastic sheet that covers the tomatoes growing in the garden, essentially a miniature greenhouse.
There should be a flap on the sheet that you can open if it starts to get too warm inside, and you will want to secure it against being blown off by strong winds.
You can make a more elaborate cold frame from old windows and hay bales or a wooden framework.
Commercially made cold frames are available at nursery supply shops.
Using a cold frame also means that you can strategically plant earlier, closer to the last frost date. As you are thinking about when to grow tomato plants, and as you get more confident about how to grow tomato’s, you may wish to start doing this in order to get earlier harvests.
Second to sunlight in terms of importance to your success while growing tomatoes is watering.
Roughly, tomato plants need about 5 cm of water per week. Water brings, among other things, essential calcium to the roots and a deficiency of that mineral can lead to blossom end rot. Because they are so susceptible to fungus disease, the foliage and stems of tomato plants should be kept as dry as possible.
On the other hand, as we have seen, the soil must be kept moist, throughout the root system, to keep the tomatoes thriving. You must therefore be careful when watering, whether you are doing so by hand or using an irrigation system, to establish the right balance of water.
Among the best solutions is to use a soaking hose system. This is a hose which is porous, or has holes placed along its sides, placed on top of the soil, which leaks water gently. A similar apparatus is a drip irrigation system.
If you plan to grow tomatoes every year, either type is a good investment.
Either can also be used to water in raised beds or containers. If you are growing in containers, you may need to water more often because water will evaporate from the sides of your containers as well as at the soil surface.
A conventional lawn sprinkler system or anything that distributes water at high pressure is not good for tomato cultivation.
The tendency for leaves and stems to be splattered with water and potentially disease bearing soil is increased.
While disruptions of the surface of the soil or mulch may not be as serious, they can still have an impact on the robustness of the root balls of your plants and is not worth the risk.
If you are watering by hand, take care to keep the stream as gentle as you can, and water at ground level. Don’t panic if you do get a bit of water on the plant. Water early in the day so any water that does get on them will dry before nightfall.
If you live in an area that receives a large amount of summer rain, you may be able to water less often.
You will, in any case, wish to be cautious to guard against overwatering. If the soil is too sodden, the roots won’t be able to get the oxygen they need. Too much water and fertilizer can also lead to cracked fruit.
Knowing your soil type will be useful in helping you learn how often to water. On average, you will most likely water twice a week. Sandy soil drains more quickly, so more frequent watering may be needed. Take a sample of your soil to your local nursery to find out what kind it is, if you don’t know. A soil moisture monitoring probe is a useful tool to help you evaluate and adjust your watering scheme when you grow tomato plants. It is inexpensive and easy to use.
Just like people, plants are most healthy when they get the right amounts of the right kind of food. For tomatoes nutrition is obtained from the soil and mulch, and through fertilizer that you provide.
There are many fertilizers available that are marketed for growing tomatoes.
They need Nitrogen, Phosphorus, and Potassium (abbreviated as N, P, and K). You will see both chemical and organic fertilizers.
The organic type is best for tomatoes. If you have access to compost, that works well. Just toss some on top of the soil every two weeks.
To help the young tomato grow, the ratio should be equal. 6:6:6 and 10:10:10 are commonly found.
Older plants, especially once they have started to flower, benefit from more phosphorus, such as 5:10:5.
Nitrogen helps leaves to grow lush and green. Too much can result in the overgrowth of leaves at the expense of fruit bearing.
Phosphorus promotes healthy roots. Potassium, also called potash, supports the development of flowers and fruit. Fruit that is too soft with poor skin condition can be the result of an overbalance of potassium.
Fertilizer granules should be covered with soil so that the nutrients penetrate better. They have the advantage of being longer lasting so you need to put them down less often.
Liquid fertilizers are mixed with water, so they are more convenient, but you will need to apply more often.
A newer development is foliar fertilizers, which are sprayed directly on to the leaves. That needs to be done early in the day, before noon, when the leaves are most porous.
A soil test kit will enable you to keep track of the amounts of N, P, and K as well as pH. Test every week or so to make sure that there isn’t too much or too little of anything.
Fertilizer may be applied either by side-dressing or top-dressing. For side dressing, dig gently around the plant to a depth of about one cm and put down the fertilizer.
Top-dressing is when the fertilizer is spread across the top of the soil.
Compost is typically top dressed, while granules are best side-dressed.
In addition to standard NPK fertilizer, there are some other things you can do that will help your plants to grow their best.
When plants are flowering, adding a calcium source, such as gypsum, to protect against blossom- end rot of the fruit. A fish emulsion solution is excellent for providing supplementary nutrients.
The foliar fertilizer sprays are usually composed of fish emulsion. It can be given once a week until flowers appear and thereafter every three weeks.
Not all insects are out to ruin your hard work by harming your tomato plants. In fact, most of them are neutral or beneficial.
Still, there are a few key pests that you will want to watch out for.
Aphids are well known to any gardener. In small numbers, they won’t do much damage, but in large numbers they can kill plants.
Tomato Hornworms are large, green caterpillars with white stripes. They can grow longer than 7 cm, but have very good camouflage so you may not notice them at first. If there are only a few, you can just pluck them off.
Some species of parasitic wasps lay their eggs on tomato hornworms, killing them. If you see a hornworm with eggs on it, you don’t need to do anything as it is already dying.
Cutworms are active after dark. They are particularly devastating to young plants, which they can kill in a single night. You can protect your seedlings by placing 10 cm wide collars of cardboard or aluminium foil around them, sunken two cm into the ground.
Both the larvae and adult stages of flea beetles eat tomato plants. The adults chew holes in the leaves and the larvae feed on the roots. Diatomaceous earth is helpful in controlling the adults. Mixing beneficial species of nematodes into the soil controls the larvae.
There are other species of nematodes that are destructive to tomato plants. Called root-knot nematodes, they live in the soil and invade the roots, hampering their ability to take up nutrients. They tend to occur in warmer climates with shorter winters, where the soil conditions remain more hospitable. They are difficult to control. Because it takes them several seasons to really establish in the soil, you may be suddenly taken by surprise.
One method for controlling nematodes is to plant a different crop in the area the next year, one that is not susceptible to them, essentially starving them out. Another option is to add earthworms, beneficial nematodes, and friendly bacteria to the soil, mixing well, to bring the soil back into balance.
Whiteflies present a double threat. They feed directly on the juices of tomato plants, and the sticky substance they leave behind can attract sooty mould spores.
Whiteflies are resistant to most conventional pesticides.
Sticky traps can be used to capture some types of insects, such as flea beetles and whiteflies. Introducing natural predators, like ladybird beetles and lacewings, into the garden helps with control of aphids and other pests.
The use of chemical pesticides is highly discouraged.
They are indiscriminate, killing good and neutral insects as well as pests. Disrupting the natural balance of your garden can have a snowball effect.
The plants themselves may be adversely affected by chemical controls.
Furthermore, you don’t want to risk any pesticide residues ending up in the tomato fruit that you are going to eat.
If you have a serious pest problem, there are some safer pesticide options.
Biologically derived pesticides like Bacillus thuringiensis or Bt, rotenone, spinosad, and pyrethrin are effective and gentler.
Always read labels for precautions and follow directions exactly, using the smallest amount you can to control the problem.
You can buy or make insecticidal soap, which is effective primarily against soft bodied insects. The potassium fatty acids in the soap physically disrupt the body cells of the insects, killing them. Insecticidal soap is relatively safe. Some plants are more sensitive to burning, but tomatoes are not particularly affected.
Smaller tomatoes varieties and those with shallow root systems can be grown in hanging baskets.
Some examples of appropriate heirloom tomatoes are Baxter’s Early Bush Cherry and Whippersnapper.
Hybrids include Floragold Basket, Florida
Basket, Micro Tom and Tumbling Tom.
A 30 to 35 cm diameter wire basket is the best choice, but any deep hanging basket will work.
Line the basket with peat moss or coir fibre and fill it with a quality potting mix developed for tomatoes.
Plant one seedling per basket.
At the end of the season, the liner and soil should be discarded as it they can hold diseases.
A recent trend has developed for growing tomatoes upside down. This is essentially a hanging pot with a large hole in the bottom, through which the tomato plant grows.
Many people have found that they really enjoy this method. It is good for those with limited space, and doesn’t require as much labour. There is no worry about soil-borne diseases and pests, which is true of all container gardening.
There are disadvantages as well. The planter can be quite heavy, especially once the plant has grown large, so the hardware to support it wherever it is hanging must be strong.
If it is hanging from an overhang that can significantly reduce the amount of full sun that the growing plant is able to get when it is smaller. Even the planter itself will cast shade over the tomato. As with upright hanging baskets only the smaller varietals are appropriate for growing upside down.
Upside down tomato pots and whole kits can be purchased, or you can make your own pot fairly easily.
When it comes to tomato plant growing, planting them in the right location is potentially the most important factor in determining your ultimate success.
These heat loving plants grow best with at least six hours of full sun daily.
You will get higher yields and your plants will be more resistant to disease with the more sun they get. It is worth your time to actually time how long an area gets sun to be sure you don’t end up cheating your tomatoes of light.
Watering and soil nutrients you can adjust, but – unless you are growing indoors with a grow light – you cannot control the amount of light that your tomatoes get, except by selecting the sunniest spot to plant them. This may also influence your decision whether or not to grow in containers.
Your location possibilities may constrain you when it comes to the number of plants and types of tomatoes that you will be able to grow. When planning your tomato garden, look at your potential locations first.
Because tomatoes tend to be susceptible to soil borne diseases, especially fungal ones, there is a conventional wisdom that they should be planted in a different area each year, rotating through a three year cycle. Obviously, this is not always possible, but it should enter into your thoughts as you are planning your garden.
Another consideration is that you will want to choose a spot to grow tomato plants that makes it easy and convenient to water. Many gardeners use a drip system or a soaker hose for irrigation.
If you are going to be watering by hand, make sure that you have plenty of room to lay down an even amount of water around each tomato plant.
One last thought on location.
Tomatoes cannot grow within fifty feet of a black walnut tree, because the tree’s roots are toxic to them.