Zucchini and other soft-skinned summer squashes are usually pretty easy to grow. But, gardeners do sometimes face struggles with these productive crops. Perhaps your vines stopped producing in mid-summer? Or the fruits were small or deformed? Or maybe your plants simply died before producing any fruits? If you found yourself asking why zucchini growing problems struck your garden, this solution guide is for you.
Squash are generally divided into two categories based on when they’re harvested and how they’re used:
- Summer squash is harvested in the summer before they reach full maturity. Because they’re harvested early, their skin is edible and they have a relatively short shelf life. Summer squash varieties include zucchini, straight neck squash (a.k.a. “yellow summer squash”), and crookneck squash.
- Winter squash are harvested in autumn after or just before they reach full maturity. This leaves their skin inedible, but gives them a longer shelf life (some varieties are capable of keeping through the winter—hence the name “winter squash”). Winter squash varieties include pumpkins, butternut squash, spaghetti squash, and acorn squash.
HOW TO GROW ZUCCHINI
Plant zucchini in full sun in compost-rich, well-drained soil. Zucchini likes to get its start in the spot where it will grow, but if you want to get a jump on the season, start seed indoors 3 to 4 weeks before the last expected frost in 4-inch biodegradable pots. A week before transplanting, harden off seedlings by cutting back on the water and lowering the nighttime temperature to 65°F.
Zucchini wants warm soil and air temperatures for growing—in the 70s°F is optimal. Zucchini seed won’t germinate in cold soil. Wait until the soil temperature has reached 60°F before direct seeding or setting out starts. Lay down a sheet of black plastic to warm the soil before sowing or planting. Plants started in chilly temperatures may become stunted.
How to plant?
- To germinate outside, use a cloche, row cover, or frame protection in cold climates for the first few weeks.
- Plant seeds about 1-inch deep and 2 to 3 feet apart in a traditional garden bed.
- Alternatively, plant as a “hill” of 3 or 4 seeds sown close together on a small mound; this is helpful in northern climates, as the soil is warmer off the ground. Allow 5 to 6 feet between hills.
How to care?
Watering
Keep the soil evenly moist. Give zucchini 1 inch of water a week. The critical time for watering is during bud development and flowering. Once plants are established, mulch with straw, hay, or dried leaves to retain soil moisture and suppress weeds. Drought-stressed plants are more susceptible to insect attacks.
Feeding
Zucchini are heavy feeders. Prepare the planting bed with lots of organic matter—a few inches of aged compost spread across the bed and then turned under. If leaves grow pale or plants seem weak, side-dress zucchini with well-aged compost or use a foliar spray of liquid fish or kelp fertilizer—high in phosphorus for fruit production. Don’t use a fertilizer too high in nitrogen; it will diminish your yield.
How to harvest?
Zucchini should be picked young and tender for the very best flavor. Once fruits are 4 inches long, it’s time to start the harvest. Zucchini can grow 1 to 2 inches a day so check your plants every day at harvest time. Zucchini that grows very large will be pulpy, seedy, and bitter flavored.
ZUCCHINI GROWING PROBLEMS
Squash vine borers
One of the biggest zucchini growing problems is a pest known as the squash vine borer. Adult vine borers are day-flying moths that are black and red with dark wings. They’re fast flyers, so gardeners don’t often spot them. The damage caused by their larvae, however, is difficult to miss. Squash vine borer larvae feed inside the main stem of the plant, hollowing it out and eventually causing plant death.
Poor pollination
Zucchini and other squash are insect-pollinated, meaning a bee, beetle, or another pollinator is needed to move the pollen from a separate male flower over to a female flower. If there aren’t enough pollinators present, puny or deformed fruits are the result. If your zucchini are mal-formed and stubby on the blossom end, poor pollination is the most pressing of your zucchini growing problems. To improve pollination rates, plant lots of flowering herbs and annuals in and around your zucchini patch.
Poor soil
Zucchini doesn’t require excessively nutrient-rich soil, but it does perform best in soils that are high in organic matter with a soil pH of around 6.5. If your pH is too far off that target mark, the plants may fail to produce quality fruit because the soil pH affects the availability of many different nutrients.
Squash bugs
When it comes to insects that attack squash, none are more difficult to control than squash bugs. These shield-shaped, brown insects suck out plant juices with their needle-like mouthpart, causing stippling, yellowing, and browning of the leaves.