How to Grow Lettuce, Spinach, Kale, and Other Leafy Green Vegetables

One of the first crops I harvest from my garden every year are leafy green vegetables like spinach, kale, romaine lettuce, arugula, young leaves of Bok Choy and domesticated dandelion (along with asparagus, of course). Together, that’s one great spring salad or stir fry.

I typically begin the seeds for these leafy green vegetables indoors in March under grow lights. Then, around the time of my last frost date (mid-May), I transplant the seedlings into my garden. Many gardeners transplant leafy green vegetables 30 days before their last frost, but in my garden, that never seems to work out. Sometimes the soil is too cold, which slows growth, or a surprise killing frost appears. And then, of course, the rabbits… those damn rabbits. Because these tender vegetables are a glorious buffet for Bugs and his buddies trying to fatten themselves up after a long winter when there is little else to nourish them. If I wait until May to set out the plants, the rabbits are a little kinder, because there is so much more to eat. Better safe than sorry.

Leafy greens and small, fast-growing brassicas like Bok Choy can also be grown easily by seed sown directly in your garden (or in containers). But wait until your last frost date has passed, because if the soil is too cold, the seed will be slow to germinate. And watch out for birds – most leafy green vegetable seeds are broadcast on the soil surface or covered with only a dusting of soil – I’ve actually seen Robins watch me plant and then swoop in and pick through the soil once I’ve left the garden.

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Where and when to plant kale, lettuces and other leafy green vegetables

If started indoors, plant tender leafy green seedlings after your expected last frost date. Hardier seedlings like Kale can be planted 2-3 weeks before last frost. If sowing from seed, wait until all threat of frost has passed. Greens can then be succession planted at 2-3 week intervals for a harvest all season long right through fall.

Leafy greens benefit from late afternoon shade to protect them from intense afternoon summer sun and heat. Intense sunlight may cause sunscald; high heat, especially prolonged heat, can slow their growth and inhibit their development. Shade can be provided by other tall-growing plants like corn and tomatoes, fruiting shrubs, trees, a garden shed, just about anything.

By far, you’ll achieve the best flavor from leafy green vegetables during the cooler times of the growing season – spring and fall. That’s why I try and get my seedlings in the ground as early as possible in spring (keep an eye on weather forecasts) and then plant seed again mid to late summer for a fall harvest. However, there are a number of varieties of kale which can be enjoyed all season – they’re very hardy plants and one of the ultimate sources of nutrition (kale/spinach/carrot/mango smoothies rock!).

Spacing leafy greens in your garden

How far apart each variety should be planted varies according to the mature size of each plant, or the size at which you plan on harvesting. If you prefer young greens as I do (they’re much sweeter and more tender), plant them close together to get the benefit of shading one another from excessive sun and heat. And as they mature, gently pull them out by the root and pop them in your mouth – greens can be eaten at any stage of development, even as sprouts.

How to fertilize lettuce, spinach, and other leafy greens

Lettuces and small brassicas do well with just a compost feeding, but work the compost into the top layer of soil before planting seed. When the plants are 2-3″, or after you transplant seedlings, add more compost around the plants (but not touching them). If your soil has been depleted by a heavy feeder like corn the year before, you may want to add organic fertilizer with significant nitrogen (like guano) a week or so before planting or transplanting. Aside from that, greens need very little fertilizer.

Which pests bother kale, lettuce, spinach, and other leafy greens?

Greens are very tender vegetables and are subject to all kinds of pests, especially if the plants are stressed by frost or heat. Even more deadly are rabbits, birds, and squirrels. You can’t do much about the birds, but a good layer of Liquid Fence delivered every week or so keeps the rabbits and squirrels at bay. But if you’re in Deer country, you better build a fenced-in area, with a top – basically a cage. I have a gardening friend who can’t get past a few weeks without the local deer population cleaning him out.

As far as disease, the biggest problem with leafy green vegetables is forms of mold such as downy mildew. If the early season is very wet, mildew spores coat the plants quickly, multiply, and overtake them. There are some organic solutions to combat mildew, but they must be applied before the mold infects the plant.

Once infected, don’t bother trying to save the plants – they become inedible. If your season’s rainfall and humidity are relatively normal or dry, mildews and disease shouldn’t be a problem. But you should always exercise caution and thin your plants as they grow, to ensure good air circulation around each plant. Compost is one of the most efficient barriers to mold spores.

As far as insect pests, that largely depends on where you live. In more moderate areas like the mid-Atlantic, insect pests are few. But in warmer regions, you might be wise to use netting over your greens. Stress on the plants is a big determinant as to their susceptibility to pests. Poor transplanting, slow seed germination, too much water, too much heat, over-fertilization, etc., weaken the plant and make it an easy target. I never recommend using insecticide of any kind on your greens – in many cases, blasting your plants with a hard stream of water is sufficient to knock pests off, or they can be picked off by hand. I also recommend developing a bird habitat in your backyard – birds eat an enormous amount of insect pests and can be a gardener’s best friend.

When to harvest lettuce, spinach, kale, and leafy green vegetables

As mentioned earlier, leafy greens can be harvested at any stage of development, but young greens are by far the tastiest. Many varieties are cut-and-come-again, meaning you can harvest leaves whenever you like and leave the plants in place to grow more leaves. How deep into fall you can harvest depends on your local weather conditions and the cold hardiness of the variety. In my area of Pennsylvania, I can still harvest Kale well into October and sometimes November. Bon Appetit!

Learn how to interplant greens with your other veggies with our companion planting guide.

We garden in Pennsylvania, United States, zone 6B. Much of the info we share is based on gardening in our temperate area. But many of the flowers, vegetables, and fruit we write about can be grown in soil other than ours (clay) and significantly different weather conditions and elevations. You might need to choose specific varieties for your region, modify your garden, add soil amendments, or adjust the soil pH to match our results. Please check your local university extension website for specifics for your area.