Summer Squash Planting Guide

Summer Squash Planting Guide

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Squash is a rewarding crop to grow for both novices and experienced gardeners both; few vegetables produce so much harvest with so little effort. The most difficult job required for Summer squash is to keep them picked! Squash originate from the Americas and adapt well to most soil types. All squash plants have both male and female flowers, requiring both to set fruits that develop to maturity. Plant after last frost, and start harvesting in as few as 40-45 days – and they produce like crazy. Harvest summer squashes all summer and consume them when they are small and tender for the best taste and quality.

Soil Preparation

Squash prefer a sandy soil, rich in organic matter, well drained, and not too heavy. They also need full sun exposure. Before planting, incorporate 1-2 inches of well composted organic matter, Humic, and 1 lb. of all-purpose fertilizer (we recommend “That’s all it Takes” complete fertilizer or Happy Frog Organic Tomato & Vegetable Food) per 100 square feet and work them in to a depth of 4-6 inches. Heavy, clay-based soils must be amended with compost and organic matter to encourage and allow for good root development. For best results, add 2-4 inches of a variety of different types of organic matter and 50 lbs. of Zeolite soil conditioner per 100 square feet each fall for multiple years to increase drainage and nutrient availability. By doing this yearly, over time you can create a better growing environment for your garden plants to thrive in and produce. Please consult our Soil Preparation Guide in the attached appendix.


You can successfully grow squashes from start or seed, it just depends on the preference of the grower. The seeds can also be sown indoors for starts 2-3 weeks before the last frost date. If planting directly outside, it is possible to do it after the last frost of the season (which for Cache Valley is around Mother’s Day). For earlier starts, use plastic water walls, row covers, or hot caps to protect against frost danger. Seeds should be planted with 4-6 seeds per cluster, about ½ inch deep and 4-6 feet apart. Squashes are commonly grown in “hills,” which is not really a hill, but more like a depression that will keep the seeds and water contained in the same location, and for an easier harvest. After the seedlings have two leaves, you can thin them to 2-3 plants per hill, or leave them all to grow. The vines will spread out to about 4-5 feet in diameter, so be sure to leave at least 6 to 8 feet between each hill or row. Some squash come in a bush variety that won’t take up as much space, usually 20-30% smaller than a normal bush.


Summer squash come in a variety of sizes, shapes and colors. Spacemiser (Black Coral) produces narrow, long, green zucchini in a very compact bush. The fruits stay smaller, longer, but will eventually grow into mammoth boats if you let them. Fancycrook squash has a smooth, yellow skin with little or no warts – unusual for a crookneck – and outstanding flavor. Just for fun, Summer Surprise mix medley has green, yellow, gray, striped, and a Lebanese type zucchini all mixed together. Scallop squash look like little white or yellow flying saucers.


Squash need regular water and consistent soil moisture to produce well. Use of a soaker hose, drip system and light mulches or weed barrier can assist in maintaining correct soil moisture and guaranteeing a healthy harvest. We recommend about 1-2 inches of water applied per week in 2-3 applications. Moisture fluctuations can cause problems with flower set, and poor yields. Maintaining consistent moisture will prevent early flower drop, proper pollenization, and assist in greater root development. Summer squash use a lot of water, so make sure to keep them moist.


About 6 weeks after germination or transplant, apply a balanced vegetable food (“That’s All it Takes” or Happy Frog Organic Tomato & Vegetable Food) around the base of each plant and water thoroughly. ½ to 1 cup per 10 square feet of area works well. For quick bursts of growth and flower production, we recommend using a water soluble fertilizer like Ferti-lome Blooming and Rooting or Grow Big from Fox Farm once per week for extra productivity. Just mix in water and apply to the leaves as well as the root zone.

We also recommend treating your squash seed or plants with beneficial microbes and mycorrhizae (Kangaroots or Myke). These added helpers bring nutrients and water directly to the plants that host them, making them stronger, more resistant to insects and diseases, and more drought tolerant. Don’t go home without them.

Common Problems

Anyone who has ever grown squash knows of the problems that can accompany this garden vegetable. Aphids, spider mites, blossom end rot, can all damage a squash crop. Powdery mildew, a white-patchy disease that stunts the plants growth and eventually will kill the whole vine, can easily be taken care of by Natural Guard Copper Soap (organic) or Ferti-lome F-stop. If squash bugs are present, a once healthy plant will suddenly drop like it’s not getting enough water. The eggs, which are seen on the bottom of the leaves, are a coppery color. These can be physically smashed or removed. The bugs themselves are black, shiny, oval-shaped beetles; they sting the vine and stop water and nutrients from getting to the rest of the plant. Spray with Hi-Yield Indoor/Outoodr Incecticide or dust with Hi-Yield Garden Pet and Livestock Dust. Organically repel bugs with Natural Guard Cedar Oil Granules. For a simple solution, mix Fertilome Fungicide 5 with Kangaroots and any pyrethroid insecticide labeled for vegetables and water your plants with it every week - leaves and roots. It will control every possible pest that can damage your plants.


Fruits are usually ready by late June and will produce until frost in the fall. Use a sharp knife or a hand pruner to cut the squash from the plants, making the cuts close to the fruit – this will encourage the plant to produce more. Consume shortly after picking, but the fruits will hold well when refrigerated for a week or two.

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1 comment

I enjoyed the article with so much good information. I’m wondering, my plants are starting to produce yellow crook neck squash and I’m wondering if it’s ok for the squash to lay on the ground and dirt or should I mulch the squash to keep it off the dirt and to avoid any rot from the ground. Thank you for any suggestions.

Catherine Cox

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