5 Tips for Growing Great Zucchini in Raised Beds

Zucchini, a summer squash, is one of my summertime favorites. Whether grated into batter for bread, grilled on the barbecue, or even raw in a salad; it is freaking delicious. It’s known for being an easy, prolific grower and generous giver of its fruits (botanically speaking, zucchini is a fruit). Zucchini is a must-have for the summer garden, whether grown in the ground or in raised beds. 

Raised bed gardening is great for many reasons, including weed management, precise control over soil and amendments, and many others, all leading to healthy plants and increased production. While most zucchini plants need a lot of space to spread out, with the proper planning, you can still have an excellent yield in a raised bed. 

Prepare your soil

My number one rule of successful gardening starts with the soil. To thrive, zucchinis need rich, warm, well-draining soil in full sun. Ideally, the soil has a slightly acidic pH between 5.8 and 6.8. Raised beds are a common way to ensure adequate drainage, as zucchini plants hate wet feet. 

They’re heavy feeders, so your soil needs to be rich. Three to four weeks before planting, a generous dose of aged manure, sieved compost, fish emulsion, or organic all-purpose fertilizer is a great way to crank up the nutrients in your soil. With your soil freshly amended, topdress with mulch to discourage weeds and help the soil maintain moisture. As your plants start flowering, give them another dose of fertilizer or work a generous amount of organic matter around them. 

They don’t like to be cold – their ideal temperature is between 60°F and 85°F (16 and 29°C), though they can tolerate low temperatures down to 40°F (4°C). When planting, the soil needs to be at least 70°F (21°C). If you have a shorter growing season with a late frost date, use a tarp to warm the soil four to six weeks in advance. 

Choose the right zucchini for your space

Zucchini is a popular plant, with many varieties to choose from! There are two main types: bushing and vining. The more compact, bushing varieties best suit raised beds and containers and provide the greatest yields. 

Squash plants are monoecious, meaning they produce both male and female flowers. This is important to fruit production because the female flowers need to be pollinated to fruit. Most of the time, this isn’t an issue as bees and other pollinators do this part, but if you’ve had problems with pollination in the past, I recommend doing two things:  

• Plant pollinator plants like anise hyssop, astilbe, bee balm, borage, white alyssum, calendula, clover, phacelia, and sunflowers to attract bees. 
• If this doesn’t work, hand-pollinate your flowers with a paintbrush or cotton swap by rubbing the pollen from a male flower and transferring it to a female flower.  

Direct seeding versus transplanting

The best way to seed zucchini is to seed them directly in warm soil one to two weeks after the last frost date. Squash plants are completely intolerant of cold weather, so wait until the soil temperature is consistently about 70°F (21°C) before seeding. While vining types need two to three feet of space between them, bushing varieties only need one and a half to two feet of space. 

However, if you live in a colder climate (zone 5 and below), start your seeds indoors about a month before your last frost date for the best growing season. About a week after your last frost date, harden your seedlings to acclimate them to temperature fluctuations. After two or three weeks, when nighttime temperatures drop no lower than 40°F (4°C), plant your seedlings into your raised beds and thin them if needed.

Be very, very careful with their delicate root system when transplanting – they are famously averse to having their roots disturbed. 

Avoid plant stress 

Healthy, stress-free plants produce the greatest yields. While zucchini plants are very resilient and easy to grow, they’re not immune to challenges that negatively impact their health. 

Zucchini is especially susceptible to powdery mildew, and the best way to avoid this is by providing ample space between plants for good airflow and watering only the base of the plant – not the leaves. 

If you see your zucchini wilting under afternoon sun –  don’t panic and overwater them. Check the soil first, and if it’s still moist – don’t worry. Zucchinis can be a bit dramatic in the afternoon sun. They’ll perk back up when it cools off. 

Harvest at the right time

Harvesting zucchini when the fruits are small-to-medium sized helps you, the grower, enjoy tasty, tender zucchini. It also helps the plant continue producing high yields—overripe zucchinis hinder production for the rest of the plant. The best time to harvest zucchini is when the fruits are about four to eight inches long, depending on the species. Try not to pick them when the plants are wet to prevent potential disease. 

If you do find yourself with an overripe zucchini, toss it into the compost bin or use it to bake zucchini bread or zucchini parmesan. That said – it’s best to prevent this from happening in the first place. Zucchinis grow fast and should be checked every other day for ripe fruits. If you’re going on vacation and don’t have anyone to look after your plants, pick off all of the small fruits before leaving. 

Their gorgeous flowers are also edible – and delicious! Use squash blossoms in quesadillas, add them to pasta with butter, stuff them with fillings, or fry these tender blossoms.