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May

This calendar’s monthly planting guidelines are based on USDA zone 9, but they are adaptable to most zones. To find your zone, go to the National Gardening Association’s website. If your zone is 7, 8, or 9, you can safely use this guide. If your zone is 4, 5, or 6, then add a month before beginning your spring tasks and start your fall tasks a month earlier. If your zone is 10 or 11, subtract a month to your spring tasks. Your fall and winter tasks should remain the same as the original guide if you are in zones 10 or 11. These are all general guidelines. Your specific microclimate, which depends on distance to a large body of water (like gigantic lakes or oceans) and elevation, will make your zone fluctuate. Consult your local county extension office to get more detailed zone and planting guide information.

Tasks for May:

  • Planting
  • Stay on top of weeds
  • Check for bugs
  • Initial staking
  • Spray with worm casting tea and aspirin

Planting

If you didn’t plant in April because of weather or are still planting, May is the month to do it. Also, this is a good month to identify any struggling tomatoes you may have already planted and replace them with healthier stock. Tomato seedlings at nurseries are cheap. Your time and garden space are not cheap. Replace funky plants with something good and simply move on.

Stay on top of weeds

Weeds make safe harbor for detrimental insects in the garden. Thrips, one of the worst enemies of tomato plants, overwinter on weeds around our garden. After the weeds die, thrips fly onto our tomatoes and other plants in the garden, quickly infesting them with diseases that kill or greatly stunt their growth.

Weeds also deplete moisture and nutrients from the tomato beds, leaving less behind for our desired plants. If you’ve amended the soil, then you’ve already spent considerable time and money on your garden. Don’t let a few missed opportunities to do your weeding undermine that effort.

Don’t spray your weeds with herbicide. The spray droplets will no doubt drift onto your good garden plants and kill them or seriously damage them. Herbicides are also harmful to honeybee populations and other beneficial insects.

Check for bugs

You should already have a jeweler’s loupe that you’ve used earlier this year to check out your seedlings before purchasing and planting. If you don’t have one yet, purchase one online that’s a 20x magnification and has an LED light on it.

To properly use a jeweler’s loupe, hold it up against your dominant eye and bring the leaf up to the loupe. You can remove a leaf from one or two areas of your tomato plant to do this task—the leaf won’t be missed. Be sure to remove the leaf using garden clippers, not your fingers. You’ll end up likely tearing plant material left behind or, worse yet, snapping the tomato in half if you try to remove a leaf without the aid of sharp garden clippers.

Google the following insects to understand what they and their damage look like: thrips, psyllids, tomato russet mites, aphids, spider mites, whiteflies, earwigs, pillbugs, flea beetles, cutworms, tomato fruitworms, tomato hornworms. The first several are only visible using the loupe. The other, larger bugs can be seen with the naked eye, but it takes knowledge of what the pest looks like and an astute, careful inspection several times a week.

Anything detrimental spotted should be dealt with immediately. Don’t think they’ll go away on their own; they’ve found their meal and they’re going for it. Some of these bugs aren’t just putting unsightly holes and bites into fruit and leaves—they are actually imparting diseases to the tomato plant-like “psyllid yellow,” curly top virus, and tomato spotted wilt virus, among others.

There are organic pesticides for each of these pests. You should have in your garden shed arsenal: pyrethrin, spinosad, diatomaceous earth, and Sluggo with spinosad at a minimum. Use each according to its directions when you see these pests. And don’t think just because you can’t see them they’re not there. Again, many are microscopic, and some are night dwellers, coming out to feast after you’ve gone to bed.

You can also delve into the relatively new world of purchasing predatory insects that will fight your bad bugs. It seems like agriculture scientists find a new beneficial bug and the means to cultivate it and sell it every few years. So even if there’s not a predator now for something that’s bugging you and your plants, there may be shortly. Check online to see what predatory insects can help curtail your plant bugs.

Don’t assume every insect is harmful. Your mantra should be “innocent until proven guilty.” Don’t willy-nilly kill bugs with chemical “kills all” pesticides. The beneficial bugs are needed. As a good gardener, you should know what they look like. Google images of ladybug larvae, lacewings, soldier beetles, praying mantises, thrips predators, minute pirate bugs, and aphid midges, among others. Leave these alone to help your garden. There’s a saying: “When we kill off the natural predators, we are left to do their work.”

Initial staking

Now that your plants have been in the ground a few weeks, start the staking process using small, conical tomato cages, cheap and easily found at your local garden store. These small metal cages are just the beginning. You may find various sizes and kinds at the store, but you’ll just need the wimpiest ones right now. These cages just buy you some time before you use much larger and beefier cages next month. The small cages also serve to center your plant inside the large cages you’ll use in June.

Put the cages on your plants this month. Don’t wait until they get bent over from wind or rain. They’ll naturally bend and droop to the ground as they grow, but this is not a good thing to let them do. They need to stand upright and keep their leaves and fruit up off the ground. Caging the tomato plants now will give you the maximum ability to get the most pounds of fruit off each plant. They will also pollinate better if they’re forced to grow upright rather than sprawling on the ground.

If you don’t have small conical wire cages or if you’re looking to save money, you can do this initial staking with a single piece of bamboo pressed into the ground next to your tomato stalk. Then tie the tomato stalk, loosely, in several locations, to the bamboo stake.

This initial staking, whether you use a small wire cage or bamboo, is only temporary. You’ll be adding another beefy cage completely over the top of either the conical cage or the bamboo stake. Stay tuned for how to make a beefy tomato cage, plus other staking methods, in the June guide.

Spray with worm casting tea and aspirin

If you haven’t already, start a weekly regimen of spraying with a “tea” made of worm castings and aspirin. These elixirs have been studied extensively on tomato crops and have been found to be greatly beneficial. Worm casting tea is a foliar feed done by spraying all parts of the tomato plant. It can even be done as the tomato starts to fruit, and getting the spray on the fruits is fine. Worm casting tea has been shown to not only help feed the plant but also decrease diseases and pests. That’s a three-in-one benefit that a simple compost tea does not have.

Aspirin spray has been shown to not only jump-start the plant’s natural immune and disease-fighting systems but also increase blossom production. More flowers usually mean more fruit. Both sprays used in conjunction weekly throughout the life of the plant have been shown to create miracles for a healthier and happier garden. Of course, your other factors must be present as well: proper spacing, sunlight, temperatures, feeding, staking, and vertebrate and soft pest management.

The recipe for the elixir is a big handful of pure worm castings in two gallons of water. Let this mixture “steep” for two days, stirring occasionally. Even better, add an aquarium pump to push air through the mixture. After 48 or so hours, strain the worm casting tea into a two-gallon garden sprayer, removing all the spent casting debris. If you don’t remove it all, it will clog your spray pump. Then add one and a half regular aspirin tablets. Make sure it’s plain aspirin—acetylsalicylic acid, a compound derived from willow trees.

After putting the top of the sprayer back on, shake or roll it to thoroughly mix it. Then pump the sprayer to activate the spraying mechanism and spray all parts of the plant with it. Try to do this in the morning, before the sun gets hot on the leaves. Also, don’t do this in the evening, when it would be detrimental to have the tomato plants go into the cool nighttime temperatures with wet leaves.

Tomatoes are very disease-prone, so various preventative measures are necessary to ward off and prevent diseases. It’s much easier to prevent than it is to cure. Planting with mycorrhizae fungi, proper spacing, pest management, and spraying with worm casting tea and aspirin are all ways to manage and prevent diseases.

To reiterate, the worm casting tea and aspirin spray not only help prevent diseases but also feed and increase blossom production, both important for a healthy and productive garden.

Resources and Documents
  • April
    World Tomato Society
  • June
    World Tomato Society

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