BALCONY GARDENING: How to grow a steady supply of salad greens
The short shelf life of those grocery-store salad mixes is good reason to stagger-plant your own to pick fresh.
Salad greens are arguably the most worthwhile of all vegetables to grow at home. With just a few pots on a small, shady balcony, you can achieve a steady supply of arugula, spinach, baby lettuce, mustards and mesclun mix. Greens have a very short shelf-life (think of the slimy mixes you've inevitably purchased at the grocery store), are carbon-intensive to transport because they take up space and require constant refrigeration, and are one of the most commonly eaten categories of vegetables. It just makes sense to grow your own salads.
With long, hot summer days, however, these crops are at risk of bolting, the process that occurs when a plant starts to develop a tall flower stalk. Greens that have bolted taste very bitter and will have small, tough leaves. Wilting, poor germination and slow growth are also issues at this time of year.
Start your summer vegetable seedlings in small pots. Photo by Rebecca Cuttler.
It’s taken me years to get really good at growing greens in the summer. The game-changer was a visit to Hollyhock earlier this year, where I spent several days learning from garden manager Holly Mackay and seeing how they grow a constant supply of huge, gorgeous lettuce heads for their famous salads. I'm now happy to say that our greens are some of the healthiest things in our garden — even during the driest summer in over a decade.
How to grow salad greens all summer long
1. Choose summer-tolerant varieties
There are hundreds of kinds of lettuce out there. Some do much better in the heat than others. We're having good luck with Olga, a summer romaine. At Hollyhock, favourite summer lettuces include Magenta, Sierra, Nevada and Marvel. When it comes to other salad greens, like arugula, spinach and mustards, some varieties do a bit better than others, but you'll likely still experience some bolting.
2. Plant just a few seeds each week
Think about how much salad your household eats each week. Then, plant enough seeds for that amount, plus a 10-per-cent contingency. Repeat the process each week. Be disciplined! Salad greens don't preserve well, and the window for harvesting them is very brief. Most salad crops can still be planted until well into September.
3. Start your seeds in small pots
Instead of planting your seeds directly into the ground, start them in small pots. You can purchase cell-packs from a garden supply store, or reuse small yogurt containers or styrofoam cups (just wash them and poke holes in the bottom first). Fill them with a specially designed seed-starting mix, or push potting soil through a mesh screen to get a fine consistency. Keep your seedlings in a shady spot until they've developed their first "true" leaves, and then carefully transplant them into the garden. By working this way, you'll be able to keep your seedlings well-watered and protected from extreme temperatures. You'll also use your garden space much more efficiently.
I'm all about mulching this year. After transplanting your seedlings, give them a week to adjust, then mulch around them. This will save a huge amount of water during our current drought.
5. Harvest ruthlessly
Don't be shy about it. If you neglect to harvest, your greens will just bolt and you won't get to eat them anyway.
6. Consider non-traditional salad greens
Kale, chard and beet greens thrive in the summer. These crops are biannual, meaning that they won't bolt until they've experienced a winter, and therefore have a much longer harvest window. Just keep in mind that these crops contain oxalic acid, a naturally occurring chemical that can inhibit the absorption of certain nutrients. If that's a concern for you, lightly cook the greens before eating.
7. Try interplanting and underplanting
Pro tip: to take things to the next level and save tons of space while you're at it, plant your greens in between your winter kale plants, or under tomatoes. Your winter kale is probably quite small right now, but as it grows, it will offer helpful shade to the greens below. We've kept our arugula going for weeks this way without bolting. Another pro tip? For a truly consistent harvest, slowly increase the volume of seeds planted each week as fall approaches to compensate for slower growth during shorter days.
Rebecca Cuttler is an urban gardening teacher, member of the Vancouver Food Policy Council and board member of the Environmental Youth Alliance. She blogs about urban food gardening at http://abundantcity.net.