Lettuce, spinach, arugula, kale, Swiss chard, and other leafy greens are some of the easiest edible plants to grow in containers. Many mature quickly, do not require a large planter, and can be harvested a little at a time throughout the growing season.
Leafy greens are especially useful for patios, balconies, decks, and small gardens because most have relatively modest root systems. Containers also make it easier to move cool-season greens out of intense heat and closer to the kitchen for convenient harvesting.
Growing leafy greens in containers
- Use a container with drainage holes.
- Fill it with quality container potting mix rather than garden soil.
- Follow the seed packet for planting depth and final spacing.
- Keep newly planted seeds consistently moist while they germinate.
- Most leafy greens grow best during cooler weather.
- Move containers to afternoon shade as temperatures rise when possible.
- Harvest young outer leaves or cut loose-leaf varieties according to the crop.
Why Leafy Greens Are Great For Container Gardening
Leafy greens are a good choice for beginning gardeners because many varieties grow quickly and can be harvested before they require the space or growing season needed by crops such as tomatoes, peppers, or squash.
Quick Harvests
Many leafy greens can be harvested young, so you do not have to wait for flowers or fruit.
Small Spaces
Lettuce, spinach, arugula, and other greens can grow successfully in relatively compact containers.
Cool-Season Crops
Many greens can be grown in spring and again as temperatures cool in late summer and fall.
Repeat Harvests
Many loose-leaf crops can produce additional leaves after an initial harvest.
Leafy Greens Prefer Cooler Weather
Lettuce, spinach, arugula, and many other leafy vegetables grow particularly well during the cooler portions of the growing season.
They can often be planted earlier in spring than warm-season vegetables and planted again in late summer for a fall harvest.
Kale, collards, and Swiss chard generally tolerate heat better than lettuce and spinach, and many hardy greens also tolerate light frost or cold fall weather.
What Does It Mean When Lettuce Bolts?
As temperatures and day length increase, lettuce, spinach, arugula, and some other greens may begin producing a flowering stalk. This process is called bolting.
Once a crop bolts, leaf quality often declines and the flavor can become increasingly bitter or strong.
Containers provide an advantage because they can sometimes be moved into afternoon shade as temperatures rise, helping reduce heat stress and extend the harvest.
You can also sow another crop later in the season. Leafy greens work particularly well for succession planting, where small new plantings are started every week or two instead of planting everything at once.
Why Containers Work Well For Leafy Greens
Leafy vegetables are especially well suited to planters because many can be grown more closely than large fruiting vegetables.
Leaf lettuce can be grown for individual heads or planted more densely when the goal is harvesting smaller leaves. Full-size head lettuces such as romaine and butterhead generally need more room than baby-leaf mixes.
Other advantages include:
- Containers can be moved as sunlight and temperatures change.
- They make gardening possible on patios, balconies, and other small spaces.
- Greens can be grown close to the kitchen for easy harvesting.
- Containers can be raised away from some ground-level pests, although they do not eliminate insect or disease problems.
- Red, green, purple, frilly, and smooth-leaved varieties can make edible containers highly ornamental.
Leafy Greens To Grow In Containers
Choosing A Container For Leafy Greens
Leafy greens generally require less container volume than large vegetables such as tomatoes, cucumbers, or peppers.
Illinois Extension recommends containers around 10 inches or larger for many leafy greens, although the amount of space needed depends on the crop, variety, number of plants, and whether you are harvesting baby leaves or mature plants.
More important than choosing one exact planter diameter is making sure the container provides:
- Enough surface area for the desired number of plants
- Adequate root depth for the crop
- Drainage holes for excess water
- Enough potting mix to keep moisture reasonably consistent
See our guide to Choosing Planter Sizes for more information about matching containers to plants.
Best Potting Mix For Leafy Greens
Fill the planter with a quality potting mix designed for container growing rather than ordinary garden soil.
Container mixes are formulated to provide a balance of drainage, water retention, and air around plant roots.
Before planting, moisten the potting mix and fill the container while leaving approximately an inch of space below the rim. This makes it easier to water without washing potting mix or seeds over the edge.
Make Sure The Planter Drains
Leafy greens appreciate consistent moisture, but that does not mean the roots should remain in saturated potting mix.
Make sure excess water can leave the planter through drainage holes.
For more information, see our Ultimate Guide To Drainage For Potted Plants .
Planting Leafy Greens In Planters
Most leafy greens are easy to start directly from seed in the container where they will grow.
Plant seeds at the depth listed on the seed packet. Requirements differ between lettuce, spinach, arugula, kale, chard, and other greens, so following the instructions for the particular variety is more reliable than using one planting depth for every crop.
Keep the potting mix evenly moist during germination. A gentle watering can, hose nozzle, or misting attachment can help prevent newly planted seeds from being washed into one area of the container.
Thin Seedlings As They Grow
Once seedlings are established, thin them to the spacing recommended for the crop and the type of harvest you want.
Plants grown for baby leaves can usually remain closer together than crops grown to full size.
Crowding full-size plants can increase competition for water, nutrients, and light while reducing air circulation through the foliage.
Use Succession Planting For A Longer Harvest
Instead of sowing an entire container at the same time, consider planting smaller sections at intervals of approximately one or two weeks.
Illinois Extension recommends succession planting for leafy vegetables in containers as a way to maintain a more continuous harvest.
As the oldest section is harvested, younger plants are already developing nearby.
How Much Sun Do Leafy Greens Need?
Most leafy vegetables grow best with plenty of light, particularly during cool spring and fall weather.
As summer temperatures increase, however, cool-season crops such as lettuce, spinach, and arugula can benefit from protection from intense afternoon sun.
One advantage of containers is that they can be moved from a sunny spring location to a spot receiving morning sun and afternoon shade as weather becomes warmer.
Watering Leafy Greens In Containers
Leafy greens generally perform best when moisture remains reasonably consistent.
Check the potting mix regularly and water when it begins drying according to the needs of the particular crop. Containers can dry quickly during warm, sunny, or windy weather.
Apply water thoroughly enough to moisten the root zone and allow excess water to drain from the bottom of the planter.
Avoid repeatedly giving only small surface applications. Deeper watering encourages moisture to reach the entire root zone.
For more help determining when and how much to water, see Watering Plants In Containers .
Fertilizing Leafy Greens In Containers
Container plants have access only to the nutrients available within their potting mix, and repeated watering can gradually carry nutrients out through the drainage holes.
Some commercial potting mixes already contain fertilizer. Check the product label before adding more.
If additional fertilizer is needed, use a product labeled for edible container crops and follow the application rate and frequency on the label. Excess fertilizer can damage roots and does not necessarily result in better growth.
See Fertilizing Plants In Containers for more information.
Harvesting Leafy Greens
How you harvest depends on the crop and whether you want baby leaves, individual mature leaves, or an entire head.
Outer-Leaf Harvest
Remove mature outer leaves while leaving the center of plants such as leaf lettuce, kale, or chard to continue growing.
Cut-And-Come-Again
Some loose-leaf greens can be cut above the growing point and allowed to produce another flush of leaves.
Whole-Plant Harvest
Head lettuce and other crops may be harvested all at once when they reach the desired size.
Harvesting in the cooler part of the day can help leaves remain crisp, especially during warmer weather.
Cleaning Freshly Harvested Greens
Homegrown produce should still be washed before eating.
Soil, insects, bird droppings, irrigation splash, and other contaminants can reach leaves even when plants are grown organically or in containers.
Wash your hands before handling harvested produce. Rinse leafy greens under clean running water and gently remove visible soil and debris. Do not use soap, detergent, or household cleaners on fresh produce.
Drain the leaves well and dry them using a clean salad spinner, clean towel, or paper towels.
Storing Fresh Leafy Greens
Refrigerate harvested greens promptly. Keep the refrigerator at 40°F or below.
Remove excess surface moisture before storage. Greens can be placed in a clean food-storage container or bag, often with a clean paper towel to absorb excess moisture.
Storage life varies considerably by crop, leaf maturity, temperature, and condition at harvest, so inspect greens before eating and discard leaves that have become slimy, badly wilted, or spoiled.
Growing Leafy Greens In Spring And Fall
One of the biggest advantages of leafy greens is the opportunity to grow more than one crop during the year.
Plant cool-season greens in early spring when conditions are appropriate for the variety. When summer heat causes cool-season crops to decline or bolt, replace them with warm-season plants or temporarily retire the container.
In late summer, sow another round of lettuce, spinach, arugula, kale, or other suitable greens for fall harvest.
Containers can also be moved to protected areas during occasional cold nights, although cold tolerance differs substantially between crops and varieties.
Common Problems With Container-Grown Greens
Bolting
Heat and increasing day length can trigger flowering in many cool-season greens.
Bitter Leaves
Heat, maturity, and bolting can cause some greens to develop stronger or bitter flavors.
Wilting
Small containers can dry rapidly, especially in sun, heat, and wind.
Crowding
Thin seedlings when necessary so full-size plants have adequate light, air, water, and nutrients.
Leafy Green Container Checklist
- Select lettuce, spinach, arugula, kale, chard, or another leafy crop suited to your season.
- Use an appropriately sized container with drainage holes.
- Fill the planter with quality container potting mix.
- Follow the seed packet for planting depth and spacing.
- Keep seeds consistently moist during germination.
- Thin seedlings according to your desired harvest size.
- Keep established plants evenly watered without leaving the root zone saturated.
- Protect cool-season greens from intense afternoon heat when possible.
- Use succession planting to extend the harvest.
- Wash harvested greens under clean running water and refrigerate promptly.
More Container Gardening Help
Sources
- Illinois Extension — Growing Vegetables in Containers
- Illinois Extension — Helpful Tips for Creating a Successful Container Garden
- Illinois Extension — Growing Leafy Greens
- University of Minnesota Extension — Vegetable Growing Resources
- U.S. Food and Drug Administration — Selecting and Serving Produce Safely
- U.S. Food and Drug Administration — Tips for Cleaning Fruits and Vegetables
