How to Plant & Grow Zucchini

Zucchini loves warm weather. Wait to plant seeds or transplants until the soil is at least 65 to 70 degrees. In warmer growing zones (including the Southeast, Gulf Coast, and Desert Southwest), gardeners can plant two crops of zucchini, one in the spring and one in the fall. In more temperate areas (zones 6 and lower), zucchini is grown as a summer crop, usually planted in May.

Zucchini needs full sun (at least 6 to 8 hours) and consistently moist soil that is high in organic matter. Some zucchini varieties are vining types that require a trellis or a lot of room to sprawl. There are also bush types suitable for container gardening and small space gardening. For the best results, match the zucchini type to the space in which you plant to grow it.

Before planting zucchini, improve the soil in the planting areas by mixing a 3-inch layer of aged compost-enriched Miracle-Gro® Performance Organics® All Purpose In-Ground Soil into the top 6 inches of native soil. This will not only improve the soil texture, but will also give plants a headstart on nutrition. If planting in a container, fill the container with lighter, fluffier Miracle-Gro® Performance Organics® All Purpose Container Mix, which also contains nutrient-rich compost. When planting in a raised bed, use Miracle-Gro® Performance Organics® Raised Bed Mix, which is specially formulated for that growing environment.

Zucchini plants can be grown from young plants or seeds. Starting with strong young zucchini plants like those from Bonnie Plants® automatically puts you closer to harvest, plus is a great solution when you get a late start on planting. When starting with seeds, they should be sown directly in the garden after all chance of frost has passed. Because the seeds sprout and grow so quickly, there is really no need, even in the coolest gardening areas, to start seeds indoors. 

When the soil has warmed up in your planting beds, plant seeds one-half inch deep, 3 to 4 inches apart, in rows that are 2 to 3 feet apart. Thin plants so that they are spaced 6 to 8 inches apart once they are 4 to 5 inches tall. 

Another option is to plant 2 or 3 seeds (bush-style plants work best) in a container that is at least 20 inches in diameter. Once seedlings are a few inches tall, trim two off at the soil line, leaving only the strongest looking plant to grow.

For best growth, zucchini plants need regular feeding in addition to being planted in the rich, nutritious soil mentioned earlier. A month after planting, begin fertilizing your zucchini plants with Miracle-Gro® Performance Organics® Edibles Plant Nutrition Granules, which will deliver continuous food during the growing season. The result? A bigger harvest than you'd glean from unfed plants! Be sure to follow label directions.

Zucchini needs steady moisture to produce large, problem-free harvests. Otherwise, the fruits are susceptible to blossom end rot, which is when the flower end of the zucchini begins to rot. Water thoroughly whenever the top inch of soil is dry. Because disease can spread easily across zucchini plant leaves, you will want to take care when watering to direct the stream at the soil and not on the leaves. Or, install a soaker hose or drip irrigation at the time of planting.

Zucchini plants are vulnerable to a number of pests and diseases, including squash bugs, squash vine borers, striped cucumber beetles, powdery mildew, and bacterial wilt. Help prevent problems by planting only after the soil has warmed and using row covers when plants are young (until they start flowering). In addition, it helps to keep vines off the ground by trellising or adding a layer of mulch beneath them. You can also use an insect and disease control spray, such as Nature’s Care® 3-in-1 Insect, Disease and Mite Control, to help protect plants. Pull up and throw away (do not compost) any plants that succumb to disease.

Harvest time depends on the variety, but generally, zucchini are most tender and have the best flavor when they are young. Large fruits (think arm-sized) tend to be mealy and full of seeds. Carefully cut fruits off the plant with a knife or pruners when zucchini are between 3 and 8 inches long. To help them store longer, harvest with at least an inch of stem still attached.