Timing those tomato plants, and identifying garden seedlings

I started my tomato seeds only yesterday, and no, that is not an April Fool’s joke. That is a goal achieved: resisting temptation to get going too early. Getting out of March tomato-free. I finally did it!

Here are the reasons I waited so long:

  • Tomatoes are warm-weather plants. They prefer a soil temperature of at least 60°F and an air temperature consistently over 50°F, including at night. They can be killed by frost, and even if it doesn’t get that cold they sulk and poke along at cooler temperatures. Put in the ground too early, they can suffer from cold injury and nutrient deficiencies, and take a while to catch up. Put into warm soil, they start growing with minimal shock and just take off. It all evens out as time goes along.
  • And yes, there are loads of devices to protect tomato plants in order to give them a head start (I own some of them) but they’re all kind of a pain to use, and I’m not in a rush.
  • Our weather patterns these days seem to include an early warming trend (March or even February) followed by lots of bouncing up and down in temperature, and a distinct chance of frost in May. Why worry? I aim to plant my tomatoes in the second or third week of May, and to keep an eye on the forecast in case there’s a chance of freezing. I’m also measuring soil temperature. I may have to wait until even later in May.
  • Considering this late planting date, the last thing I want is a tray full of giant tomato plants that don’t fit under my lights and have to be carried in and out of the house multiple times. Tomato seedlings grow fast. They are also not persuaded by that “keep the lights close to the seedling tops” business; they just crash into the lights and try to keep going. You can use a fan to stir up the air around them and help make the stems nice and stocky; you will get stocky trees.
  • I don’t have a huge amount of indoor seed-starting real estate, and this way I don’t have tomato plants jockeying for space with cool-weather seedlings that will all be in the garden soon.
Tomato plants from a previous year, pictured a couple of weeks before they could be planted

Confession time: when I was a newbie gardener, I couldn’t wait and started my tomato plants in February. It was not a success. Over the decades since, my starting time has been creeping forward. In the last few years, it’s been in the last week of March. Finally bumped up to April! My plants will not be huge in mid-May, but that’s fine; as long as they’re strong and get a chance to harden off before planting, they should settle in happily. Probably more happily than the trees of yesteryear.

On another seed-starting topic, I often hear from gardeners who have sown seeds directly in garden beds and then can’t tell the desirable plants from the weeds. As far as I can find, there isn’t one definitive source for what brand-new vegetable sprouts look like, but you can do a search and likely find an image for what you’re trying to grow. Another hint: if there are a bunch of similar sprouts that are lined up, those are probably the plant you want, assuming you sowed them in a line.

It’s important to remember that the cotyledons or seed leaves, the first leaves that show up after a seed has germinated, often don’t resemble what we call the “true leaves” of the plant, which are the ones that might look familiar to you if you’ve seen the plant before. Here are a couple of examples from plants that might be sown outdoors (although these weren’t):

A typical cabbage family seedling; this one happens to be purple pak choi, but those heart-shaped seed leaves are distinctive. Note how different they are from the true leaves.
This is a spinach seedling. The seed leaves look like grass! – except not, because there are two identical ones, and grass would put out one at a time. The true leaves are shorter and more rounded.

It’s very exciting to have seeds coming up and plants growing! Happy April!

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.

2 thoughts on “Timing those tomato plants, and identifying garden seedlings

  1. Susan Eisendrath April 2, 2021 / 10:28 pm

    Excellent blog post Erica! Thanks!

  2. RCook April 7, 2021 / 9:14 am

    Like you, Erica, I have been trying to learn to hold off on starting my tomatoes. I’m also convinced that my seedlings do better after the world has warmed up a bit. This year I made it to the last couple days of March. Congrats on holding out until April.

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