By Sommer Cartier, for Let’s Talk Plants! May 2024.
Squash, A Limitless Bounty
Growing squash in San Diego can be a fruitful and rewarding experience, given the region's warm and sunny climate. In San Diego, these vegetable plants can be quite prolific and, if properly cared for, produce more fruit than one family can eat. You might even find yourself trying to give the fruit away to friends, family, and neighbors to avoid waste.
Below are some tips to help you successfully grow squash in your summer garden
Choose the Right Variety: Select squash varieties that are well-suited to San Diego's climate and growing conditions. Some popular options include zucchini, yellow squash, pattypan squash and crookneck squash. Look for varieties that are known for their heat tolerance and resistance to common pests and diseases.
When to plant: In San Diego, you can plant squash seeds or transplants outdoors as early as late winter or early spring when the threat of frost has passed. Squash thrive in warm soil temperatures, so be sure to wait until the soil has warmed up before planting.
Sunlight and Location: Choose a sunny spot that receives at least 6-8 hours of direct sunlight per day. Squash plants require plenty of sunlight to thrive and produce a bountiful harvest. Ensure that the location has well-drained soil, as squash plants are susceptible to root rot in overly moist conditions.
Soil Preparation: Prepare the soil by loosening it to a depth of at least 12 inches and incorporating organic matter, such as compost, to improve soil fertility and drainage. Squash are heavy feeders, so it's important to provide them with nutrient-rich soil for optimal growth.
Planting Depth and Spacing: Plant squash seeds at a depth of 1 inch and spaced 3-4 feet apart. If planting multiple rows, space the rows 6-8 feet apart to allow plenty of room for the plants to spread out as they grow.
Watering: Squash plants have shallow roots and require regular watering to keep the soil evenly moist. Water deeply and thoroughly, aiming to keep the soil consistently moist like a wrung-out sponge. Mulching around the base of the plants can help retain soil moisture and suppress weeds.
Fertilizing: Fertilize squash plants regularly throughout the growing season to provide them with essential nutrients for healthy growth and fruit production. Use a balanced fertilizer or organic compost and follow the package instructions for application rates.
Pest and Disease Management: The squash bug and the squash vine borer are two major pests to squash, often causing them to collapse overnight. Squash bugs damage plants by removing sap, causing the leaves to wilt. They are also carriers/vectors of a disease called Yellow Vine Decline that results in wilting and death of the plant. The squash vine borer is a caterpillar and it’s the most devastating pest to squash plants, killing almost every plant it infests. The moth of this caterpillar deposits its eggs on the stem near the soil level of squash plants, thus setting an infestation into motion. A few weeks later, the eggs hatch and the borers drill their way into the squash stem to begin the feeding frenzy.
To address these pests, make sure you take a progressive approach, utilizing the Integrative Pest Management framework.
Cultural control: this involves proper gardening sanitation to reduce debris that acts as a shelter for pests, the use of disease resistant varieties, early planting to allow plants to fruit before they become colonized, and crop rotation.
Physical and Mechanical control: remove and squash pests and their eggs before they populate and utilize row covers to prevent pests from landing on plants. With the later approach, the row covers will need to be removed after the first onset of flowers to allow pollinators to visit the blossoms.
Biological: The native tachinid fly and parasitoid wasps are effective in killing the squash bug and preventing colonization.
Chemical control: If you decide to utilize chemicals, natural or synthetic, timing is critical. Application should coincide with the egg hatch since the nymph stage is most vulnerable to insecticides. Also, be mindful of what other insects are affected by the chemical.
Unfortunately, most pest activity occurs during the blooming stage when the flower needs to be pollinated to bear fruit. The last thing you want to do is kill those bees and other pollinating friends.
Harvesting: Harvest squash regularly once the fruits reach a mature size, typically 6-8 inches long for zucchini and yellow squash. Harvesting regularly encourages continued production and prevents the fruits from becoming overripe and tough. Use a sharp knife or pruners to cut the squash from the plant, leaving a short stem attached.
By following these tips, you can enjoy a successful squash harvest from your garden and savor the delicious flavors of homegrown squash throughout the summer months.
More squash growing advice from the newsletter archives:
Excerpted from Let’s Talk Plants! April 2010, No. 187.
In the 2010 March Meeting Report, the editors had this to say, “When Pat Welsh speaks, people listen! And not only because she’s funny, charming, fascinating and outspoken… she’s also a brilliant educator with a lifetime of hands-on experience that she’s generous in sharing in an appealing way…
… “Start your squash, corn and beans on damp paper towels which you roll up and put in zip-lock plastic bags; put the bags on your VCR (to get gentle bottom heat) and check the bags daily; plant outdoors when they sprout… Also, ‘mix it up in the garden,’ Pat advises, planting flowers among your veggies and also planting a variety of veggies. This will make it more difficult for insect pests to decimate your crops, and also make your garden more attractive to beneficial insects (and prettier for you) ... winter squash needs a long summer growing season.”
Sommer Cartier
Master of Arts, International Development and Social Change
Clark University
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