Letters from the Garden: Planting Good Seeds

Dear Sangha,

So much is happening! Right now I’ve got two main projects going: planting seeds in flats to grow them up into small baby plants, and then transplanting those starts into the ground outside. This week I want to talk about seed starting, because it’s fun, easy, and frankly miraculous. You can also play along at home.

This past week, we transplanted our first seedlings outside into the garden. They were spinach! You’ll get to see them if you finish reading this email.

Spinach starts as seeds. Seeds are incredible little packets of energy that contain just about everything the future sprout needs to put out a root and its first leaves. Water and temperature are usually the main events that tell the seed when it’s time to stop being a seed and to start being a sprout. Some seeds require a period of being cold and damp (i.e. winter, or a simulation of winter in your refrigerator), while others don’t. This is called cold stratification. Spinach doesn’t need it. We just put the seeds in some good quality potting soil, cover them up, add water, and wish them well.

Left: spinach seeds. Right: using soil block makers to make pressed dirt cubes for seeds. This is the first time I’ve used this method and so far I really love it. There’s a lot less plastic involved.

We started these spinach seeds in potting soil and protection of the indoors in order to get a head start on the planting season. Spinach can tolerate pretty cold temperatures, which is good because we’ll likely have frosts through early May, but the ground has been frozen solid until recently so nothing could be planted. By starting them early inside though, they were ready to go as soon as we could get them in the ground. It also guaranteed that we were planting big, healthy plants that can out-compete weeds and bugs.

Soil blocks ready for planting

Spinach, like lots of vegetables, doesn’t need to be started indoors. You can plant it directly outside (“direct sowing”) and it does just fine. There are some vegetables, however, which need a longer and warmer growing season than we get in New York, and therefore do need to be started early indoors and transplanted after the last frost if you want them to reach maturity before fall. Tomatoes, peppers, and eggplants are the big names in this category, but onions also need a long season.

Once the seeds have been planted and watered, it takes them around a week to sprout. The first leaves you see aren’t actually true leaves. They’re called cotyledons, and they’re part of the embryo that was contained within the seed, like a starter pack. Those give the sprout the ability to gather enough energy to then put out their first set of true leaves, which look like the typical leaves of whatever the plant is.

Spinach seedlings under grow lights. The long thin leaves are the cotyledons, and the spinach-looking leaves are the first true leaves.

Leaves need sunlight in order to do photosynthesis, which is the process of converting light into metabolic energy. Unfortunately the light that comes through a bright window isn’t usually enough, and the seedlings can get too long and “leggy” as they stretch themselves towards it. Because we have a lot of seedlings here, I built a big rack in my bedroom in which full-spectrum LED grow lights can support the growth of plants that need to be kept in warm temperatures while they’re small.

The grow light rack in my bedroom

For plants that can tolerate colder conditions, which includes spinach as well as most brassicas and alliums, they get to go outside in the cold frame. A cold frame is basically just a large bottomless wooden frame with a transparent lid, which offers a protected microclimate inside. It can actually get over 100 degrees in there on a sunny day, even if it’s in the 40s outside! Propping open the lid to vent is therefore very important. Anyway, the rack in my room was getting full, so the spinach seedlings went into the cold frame along with the onions and cabbages.

The cold frame

The day of “as soon as the ground can be worked” arrived last week, and Bianca and I transplanted all the little spinaches into the garden, where they now look much happier. Because we don’t have a deer/rabbit fence up yet, I also covered them with a row cover, which lets light and water through but provides some wind and herbivore protection for the moment. I like to peek inside and say hi to them every day.

Bianca with spinach, and then spinach in the ground

You can do all of this at home, even if you only have a sunny windowsill or a balcony. Herbs grow great in pots, and container gardening is very possible in the city. I recommend trying basil, mint, chives, parsley, cilantro, oregano, and thyme. Basil is really the star, though, in my opinion, and will grow fine in a sunny window. If you have a balcony or porch outside that gets good sun, tomatoes and peppers also grow perfectly fine in larger containers.

All you need is some newspaper, paper bags, or brown packing paper and you can make your own seed starting pots for free. Just fill them with potting soil and add your seeds, keeping them moist by misting with water until they sprout. Covering with plastic wrap also helps, but make sure to take it off as soon as they start to grow. When they get a little bigger, thin the sprouts to one per cell, and when they have a couple sets of leaves you can transplant them into a larger pot. Of course you can also skip the seed starting and buy plant starts from a garden center. Either way, the biggest challenge is making sure everything gets enough light indoors, so use your sunniest spot.

I’m curious what y’all are growing this summer. What sort of spaces do you have access to? Is there anything new you’re really excited to grow? How are your houseplants doing? Are you doing any seed starting this year? Please share! I’m at ahzmgarden@brooklynzen.org.

Lots of love,
Ella Antell