Squash do best when they are fed with a balanced fertilizer, such as 4-4-4. Choose an organic fertilizer to create a sustainable garden. First, apply fertilizer in spring, just before you plant your squash seedlings. Then, provide a second dose of fertilizer once the squash vines begin to bloom. This will carry your plants through the growing season and ensure a bumper crop of squash. In fall, work compost into your garden soil to ensure next year’s harvest will be just as good.
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What Kind of Fertilizer is Best For Squash?
Squash performs best when fed a fertilizer with equal parts nitrogen, phosphorus, and potassium. This organic 4-4-4 fertilizer contains 4% nitrogen, phosphorus, and potassium by weight. This provides a balanced nutrient profile that will encourage squash plants throughout every stage of life. We recommend organic fertilizer over inorganic fertilizer so you can have the healthiest, most natural squash harvest.
- A balanced fertilizer, such as 4-4-4, is ideal for squash and zucchini.
- 4% nitrogen encourages leaf and stalk growth.
- 4% phosphorus drives flower, fruit, and root development.
- 4% potassium helps squash plants resist disease.
Nitrogen, the first ingredient in 4-4-4 fertilizer, is responsible for squash developing healthy vine and leafy growth. This allows your squash to take in sunlight and grow even stronger. Phosphorus, the second ingredient, promotes squash flowering and fruit growth. It also helps squash develop strong roots. Potassium, the final fertilizer ingredient, is responsible for helping your squash fend off pests and diseases, ensuring it survives until harvest.
When Should You Fertilize Your Squash Plants?
Squash plants should be fertilized twice before harvest. First, fertilize your garden in spring immediately before you plant your squash seedlings. Then, fertilize them a second time when the first squash flowers bloom. This applies whether you’re growing squash in the ground or have decided to grow squash in containers.
- Apply fertilizer in spring just before you plant squash seedlings.
- Make a second fertilizer application when your squash vines first bloom.
- Till compost into the soil in fall after the squash harvest.
After the fall squash harvest, your squash vines will die off. This doesn’t mean your work is done. You should clear away the dead squash vines and treat the soil with compost to help it bounce back before next year’s harvest. For details on each of these steps, keep reading:
Spring Fertilizer Guide for Squash Seedlings
Just before planting your squash seedlings, spread 6 pounds of 4-4-4 fertilizer per 100 square feet of squash garden. Work the fertilizer into the top 3 inches of soil with a rake, shovel, or tiller. Organic granular fertilizers will lose some of their nitrogen content when exposed to direct sun, so mixing the fertilizer into the soil ensures your plants receive the most nutrients. Mix 5.5 cups of fertilizer into the soil if you plan to grow your squash in a container.
- Before planting, spread 6 pounds of organic 4-4-4 fertilizer for every 100 square feet of garden.
- If you are planting in a container, mix 5.5 cups of fertilizer into the soil prior to planting.
- Mix the fertilizer into the top 3 inches of soil with a shovel, hoe, or rake.
- Plant the seedlings in the newly fertilized soil.
Once you have mixed the fertilizer into the soil, plant your squash seedlings. Plant squash in rows with 24 inches between squash plants. Allow for 6 feet of space between rows of squash. Your well-fed seedlings will soon sprawl to cover the open ground.
Summer Fertilizer Guide for a Good Squash Harvest
Once your squash vines begin to bloom, it’s time to apply a second dose of 4-4-4 fertilizer. Use half as much fertilizer as before since this fertilizer cannot be mixed into the soil. You should distribute 3 pounds of fertilizer per 100 square feet of garden. Add 2–3 cups of fertilizer to each container if you are growing your squash in pots.
- Make a second fertilizer application once your squash flowers begin to bloom.
- Spread 3 pounds of 4-4-4 fertilizer for every 100 feet of garden.
- Add 2–3 cups of fertilizer to each squash container.
- Water after fertilizing to pull the nutrients into the soil.
- Mid-season fertilizing will ensure a bountiful harvest.
Water just after fertilizer application to help draw the nutrients down into the soil. Although squash are heavy feeders, they are relatively shallow-rooted. This means that even if the fertilizer does not penetrate deeply, it will ensure fertile soil in the upper few inches. Since this is where the majority of squash roots are present, it will have a big positive effect.
Fall Fertilization and Soil Care Tips
Thanks to your two doses of fertilizer, you should have an incredible squash crop at harvest time. However, since squash are annuals, the vines will die by late fall. This doesn’t mean your work is done though. In order to make sure your squash bed is ready for another crop of summer squashes next year, do the following:
- Remove dead and dying squash vines after harvest.
- Spread 5 pounds of compost per 100 square feet of garden.
- Work the compost into the soil to a depth of 4–6 inches.
You can use a rake, tiller, or hoe to blend the compost with the soil. Once your work is done, allow the garden to lie dormant over the winter. The compost will return nutrients and trace minerals to the soil. In addition, it will encourage the growth of healthy soil microbes. By spring, your garden soil will be revitalized and ready to support vigorous growth.
What is the Best Fertilizer for Squash and Zucchini?
All members of the squash family—from Acorn to Zucchini—will benefit from a balanced fertilizer with equal parts nitrogen, phosphorus, and potassium. Any fertilizer type with 3 equal numbers on the bag will work. 4-4-4, 10-10-10, and 12-12-12 are all popular types of balanced fertilizers. For best results, till fertilizer into the soil before planting squash seedlings. Then, apply a second round of fertilizer when your squash plants begin to bloom in summer.