Make the Most of Tomato Time!

by Jan Hersey

posted August 12, 2021 (fertilizer ratio updated on August 23)

Is there a rule about how many times you can look at your tomatoes each day, hoping to catch sight of that first blush of color, some sign—any sign—that you’ll finally be savoring that first Caprese salad or BLT after months of TLC?

After a lifetime of growing tomatoes and vegetables, my variable successes seem to have had more to do with luck than knowledgeable care.

But it was dwindling success with tomatoes that was the tipping point: the soil in one of three growing areas we’d rotated among was pumping out increasingly spindly and yellowed plants; the second had questionable soil health in some areas; and the third was just too small. Though a larger project than neither my garden partner nor I wanted, it was time for a new hoop house: he built the frame, we hoisted on the plastic covering, and I am putting to use new-found knowledge, filling it with 18 lush plants, many with catalog-worthy tomatoes among a jungle of stems.

My transition from haphazard gardener to knowledgeable tomato caregiver didn’t happen without help. The convergence of the need to build healthy soil in the new hoop house, making use of the sunny location of the abandoned tomato locations, and my desire for the “real,” chin-dripping tomatoes of my past was the tipping point I needed, in January, to sign up for an online, self-directed and interactive class, Growing Epic Tomatoes https://organicgardeningacademy.com/p/growing-epic-tomatoes. I’ve admittedly gone a bit overboard trying to stick to all the guidance, but so far (can you see my crossed fingers?), it’s paying off in spades.

The class has taught me to truly pay attention to what’s happening to the plants at every stage—including the seeds I started for the first time on March 10!—so the plants and I have, by now, had a relatively long relationship. The class also has pushed me to experiment and then pay attention—to various seed-starting mediums (watch out for coir); amount of sunshine; hoop house, raised bed, grow bags, and sundry pots. Also, pruning and trellising techniques, and soils.

Recently, I stopped by the wonderful garden that’s emerged from the vacant summer beds at Anacortes Middle School. I wanted to check out about a half dozen tomato plants I’d passed along, a donation of some unusual varieties from Southern Exposure Family Farm in Sedro-Woolley. (20+) Southern Exposure Family Farm | Facebook

While well staked and healthy, the donated plants were a bit out of control, with an over-abundance of foliage and some odd pruning choices. The Wednesday gardeners welcomed my offer to prune, something I’ve been assiduous about since taking the class. When a handful of folks gathered seeking guidance, I gave a brief demo and offered to pull together some pointers.

For them . . . and for you, I’m grateful to share some of my now accumulated knowledge, recognizing that there are many ways people have successfully grown tomatoes for centuries.

Determinate or Indeterminate? Tomatoes have two primary growth habits. Determinate varieties grow only to about 3-4 feet high and wide. They can be allowed to grow without removing any suckers and will be supported by one of those short and otherwise mostly useless tomato cages. They also produce most of their fruit at the same time, making them convenient for canning and preserving.

Indeterminate tomato types continue to grow up and out until tempered by pruning, frost, or disease. All tomatoes can take the cold down into the ‘30s; they won’t survive a freeze.

Spacing Look at the growth habit of the varieties you’ve choosen and find a balance among spacing (36 inches is good if you have the room), number of stems allowed to grow, pruning, fertilizing, and watering. The goal, among other things, is to create good air circulation, expose the plant to maximum light, and allow access to careful watering and feeding that avoids getting water on the leaves.

Mulch A substantial mulch beneth each plant holds in moisture and prevents soil-borne pathogens from splashing onto leaves. I’ve had great luck with both small bark chips and arborists’ chips.

Stems or Suckers? Each of those cute little new shoots that pop out overnight from the crotch of a stem and a leaf is called sucker, but it has the capacity to grow into a major stem! It’s up to you to take control. Determine the initial number of stems to grow based on what your spacing, trellising, and feeding options can support. One-to-five stems is a good range to consider. Don’t get greedy, as many suckers will inevitably escape your pruning snips and become space-grabbing stems.

Sun & Shade Tomato plants need as much sunshine as possible, producing fewer fruits with less light and heat. But individual tomatoes prefer being shaded from harsh sun by the plant’s leaves to avoid sun scald. These light brown, sunburned areas don’t ruin the tomato nor any seeds you might want to save, but you’ll want to cut them out for when eating.

Pruning On all my indeterminate plants (remember, don’t prune determinates, such as Roma and Taxi), I’m constantly pinching and pruning out as many of the little suckers as I find; I’ll even sacrifice some 1-2-foot stem wannabes that are crowding the main stems. It can be hard to make the cuts, especially if they’ve got some flowers. Be brave.

Not sure which are suckers? Go to the uppermost growing tip of each stem; that is what should be allowed to continue growing; to maintain a well-behaved plant, pinch or snip out all suckers growing from the stem-leaf intersections below the growing tip. Beware—the growing tip could be an escaped sucker that might be be better thinned out.

In addition to suckers, it’s also prudent to prune off the lowest leaves up to about a foot, particularly if you’re hand watering, so as not to splash soil-borne disease organisms onto the leaves. To aid good air circulation, also prune out some of those coarse, thick-stemmed leaves with no flowers where they’re fighting each other for space.

Disease Alert! One final and very important pruning tip is to immediately prune off any mottled or discolored leaves that appear on the plant; this usually starts at the bottom. Often, this is early blight and the result of soil-borne pathogens splashing onto the lower leaves. Don’t hold back—a plant can continue to ripen its tomatoes with as little as 20% leaf cover. IMPORTANT: To prevent the spread of disease from one plant to another, keep a small bottle of alcohol handy and spritz your clippers and hands before you move on to tend the next plant. All infected leaves go in the garbage, not the compost pile, to prevent spreading the blight or other spores!

A lush Taxi determinate just before it received a severe haircut—early blight had spread far up the plant. Fingers crossed that the 40 or so tomatoes continue to ripen!

Stimulating flowering & fruiting
1) Be prepared to switch up your fertilizers. A high nitrogen fertilizer (the “N” in N-P-K on the label) is great to get the plants growing. Fish emulsion (also blood meal, feather meal, and manures) works well for this, or any fertilizer or amendment with the first NPK number higher than the others.

To flower and fruit, however, tomatoes need increased phosphorous and potassium (the last two numbers on the N-P-K label). Once the plants start flowering, I switched to a fertilizer with higher P and K, like Neptune’s Harvest, which is 2-3-1.
2) Tomato flowers are self pollinating, i.e., the male and female parts needed for fertilization are on the same flower. You can give our winged pollinators a hand by helping to stimulate fertilization by vibrating the flower stems (just as flowers are opening seems best); get your timing right and you’ll see a cloud of pollen. I use an old electric toothbrush to do this, you also can buy a product called a VegiBee, flick the stem cluster with your fingers, or simply tap or shake the support cage to jiggle things around.

If we’re headed for a hot spell, get out there ahead of the high temps and pretend you’re a bee to jump start pollination because high humidity and/or temps 90 degrees and above make the pollen sticky, it doesn’t move around, and fertilization may not occur at that flush of flowers.

Watering Water from the bottom and avoid getting leaves wet—moisture can act like glue to soil- or air-borne pathogens.

Then, whatever you determine is the best watering regime for your plantings, stick to it! Drip irrigation is best if you can manage it. Inconsistent watering is the main cause of blossom end rot (BER). When tomato plants go dry, they can’t take up the phosphorous and potassium essential to flowering and fruiting; adding calcium or eggshells at this point won’t help, it’s the uptake that’s the problem. And, when plants suddenly get a large amount of water (to make up for our absence), they’re more apt to split.

Watering intervals will vary depending on what medium plants are growing in, their exposure to sun, etc. My in-ground, hoop house plants can go 3-4 days between watering; my grow bag tomatoes need water at least every other day, as they’re growing in a lighter, fast-draining medium. I often check moisture levels with an inexpensive (about $15) moisture meter, but then, I’m a detail-oriented Virgo.

Water carefully when a plant’s growth habit, like these Cherokee Purple indeterminates, makes it difficult to keep the bottom leaves pruned off.

Feeding Tomatoes need our help to give us their best show. Feed plants in grow bags and containers every 7-10 days: the relatively small amount of growing medium (I’m using mostly 10-gallon bags) in a container drains quickly and contains little of its own nutrients. However, I feed in-ground plants less often, every 10-14 days, as they have access to soil nutrients and are in slower-draining soil. On days you are feeding, skip the watering.

Harvesting You’ve bought mozzarella, are keeping the basil flourishing, now, beat the critters to your prize fruit for the Caprese salad by picking at what’s called the “breaker stage.” This is when a tomato first starts to “color up.” It will ripen just fine in your house or garage—maybe even faster if you have a tray of tomatoes all giving off ethylene gas. Contrary to expectations, breaker stage tomatoes contain the same amount of flavor as their vine-ripened counterparts. Picking early also gives you more time to choose and use your tomatoes as they ripen instead of suddenly being faced with a basket of ripe tomatoes that need immediate attention.

Regardless of its color (today there’s a rainbow of tomato colors), you’ll know when a tomato is ripe when the flesh gives slightly when pressed. There also can be a slight change in skin color or transparency, but this info is above my pay grade.

Seed saving If you’re into saving seeds for next year’s tomato crop, do so from the first tomatoes to ripen and/or those lowest on the plant. These are the least likely to have been cross pollinated with pollen from another nearby variety.

So, while my classmates from across the country in hotter or sunnier zones are showing off their rainbow-colored trays of heirlooms, I’m watching carefully for those first signs of color on my Black Krims, Cherokee Purples, and San Marzanos!