Growing Leafy Greens From Seed to Harvest (2024)

“No matter how long the winter, spring is sure to follow.”

It’s a good bet that the person who wrote this English proverb was tired of winter and anxiously anticipating the sunny, warmer days of spring. Some years, the cold days of winter seem to last so long that the sight of a little shoot coming up from the ground can feel like a tonic.

Those tiny, light green wonders are the sign of warmer days ahead, renewal and growth, and for those of us impatiently itching to get outside with our hands in the soil, leafy greens are the answer. Most leafy greens are happy to grow on those cool, not-yet-spring days. They provide early gardening gratification and depending on how they are harvested, can produce for a surprisingly long period of time.

Leafy vegetables are nutritional powerhouses that can be eaten mixed in salads and sometimes used interchangeably in recipes. Lettuces fall into this category, but also others like kale, chard, spinach and mustards. Penn State Extension’s website has extensive information on the nutritional value on leafy greens.

However, gardeners should be aware that within the category of cool season leafy greens there are many families, and they should be rotated in the garden to avoid problems with pests and diseases. Chard and spinach belong to the Amaranth family, and kale, collards, arugula and cabbage belong to the Mustard family – Brassicaceae. Asian greens such as bok choy or tat soi will fall intothis family as well. Lettuces belong to the Aster family – Asteraceae, along with dandelions.

Planting Your Greens

Cool season vegetables can be started from seed indoors, directly seeded into the garden, or purchased as seedlings. Most will germinate in the garden when the soil temperature is between 55 to 70 degrees Fahrenheit. A cold frame or season extender can help get the jump on your cool season crop and protect young plants.

Seeds sown indoors can be started as early as four to six weeks before the last frost, and outdoors seeds can be sown as soon as the soil can be worked. Most leafy green vegetables mature quickly, in approximately 40 to 70 days, and can be planted strategically to have a continuous harvest.

However, most are also sensitive to bolting due to high air and soil temperatures and lengthening days, and therefore must be planted early in the season. Spinach, lettuce and arugula are the least tolerant of warmer, early summer days, with mustards and Asian greens in the middle, and chard, kale and collards able to tolerate the warmest temperatures before becoming bitter and inedible.

Gardeners wanting to extend their crop of spring greens into early summer should look for varieties that are labeled “heat tolerant” and try to keep their greens cool with a little shade.

Growing Greens

Leafy greens grow and mature quickly and need consistent soil moisture to avoid stressing the plant and making it more prone to bolting. Regular watering also helps cool the soil as spring days get warmer. Fish emulsion or side dressing of an all-purpose fertilizer works well for fast growing greens.

Thin seedlings as needed using pointed tipped shears or scissors to avoid disturbing neighboring seedlings. Thinned seedlings can be harvested and consumed. Control weeds and keep soil moist and cool with an organic mulch. Weeds can be hand pulled or cut at soil level.

The most common pests that bother leafy vegetables are aphids, cabbage pests such as harlequin bugs, cabbage worms and flea beetles. Click here to learn more about how to control these pests.

Harvesting Greens

Because leafy greens are vegetables that do not bear fruit, it's always hard for the beginning gardener to know when they are ready to harvest. The answer is, whenever you’re ready!

Tender, baby leaves can be harvested on leafy greens by taking the outer leaves first and leaving the inner leaves to develop. They can also be harvested all at once or they can be harvested by cutting the leaves with a sharp knife, leaving the crown 1 to 2 inches high to develop a second harvest. If harvesting by this method, the plant should be fertilized a few weeks after harvest and kept well-watered.

Nutritionally, leafy greens contain fiber, antioxidants and vitamins and are considered a vegetable building block in the USDA’s MyPlate dietary guidelines.

Planting leafy greens in your garden can make reaching the goal of a well-rounded meal easy by having them conveniently growing outside your door. Best of all, you can stay warm and cozy inside, while your leafy greens are perfectly happy in the cool and brisk temperatures of early spring.