Top 10 Questions About Squash Plants

By Nikki Tilley | March 26, 2017
Image by sarahdoow
by Nikki Tilley
March 26, 2017

It never fails”¦each year we plant a garden and care for it lovingly only to have pests, disease or other issues shatter our dreams of success. Gardening Know How got started by having a desire to help fellow gardeners with answers to all those beguiling questions that plaque us all. How to treat insects, what special care is needed for a specific plant to grow, why leaves are turning yellow or brown, etc. Growing plants like squash, for instance, isn’t difficult once you know the basics for proper care and answers to common problems that pop up along the way. Here are the top 10 questions about squash.


1) Why are the squash fruit rotting?

Most likely, they have blossom end rot. Squash blossom end rot normally happens due to a calcium deficiency. Calcium helps a plant create a stable structure. If a plant gets too little calcium while the fruit is developing, they will not sufficiently grow. In particular, the bottom of the fruit, which grows the fastest, is affected. Generally, this rights itself later in the season, but you can help the plant along by providing adequate water and nutrients to the soil, especially early on and during fruiting.


2) How to treat powdery mildew on squash plants?

Powdery mildew is common in vining plants, especially squash. Neem oil is helpful in treating this fungus as is sodium bicarbonate (i.e. baking soda). Prior to using baking soda, water your plants thoroughly and test it on a small section of the plant to make sure that it doesn’t suffer any bad reaction. Add about 1 tbsp. of baking soda to 4 cups of water and 1/2 tsp. of liquid soap (don’t use any with bleach). Mix in a spray bottle and mist the infected plants, including the undersides of leaves. Repeat 7-10 days. Spray in the morning or evening.


3) Why do squash blossoms fall of plant?

Blossom drop is typical behavior for a squash plant. They will produce mostly male (non-fruiting) blossoms early in the season and will gradually start to produce more female blossoms as the season progresses. The male blossoms typically drop from the plant and seemingly disappear. Give it some time and you will see it start fruiting. Eventually, the squash vine will produce more blossoms and these will be a more even mix of female and male blossoms. The male blossoms will still fall off the vine, but the female blossoms will grow into squash.


4) What to do about squash plant borers?

The squash vine borer has to be one of the most hated pest of this plant. You may need to rotate your squash plants (i.e. move them to another location). Planting them in the same area year after year makes them more prone to these pests, making treatment of the problem more difficult too. Other than that, the best treatment is to start treating plants in the spring with an organic pesticide called neem oil, which is safe for people and beneficial bugs, and is absorbed by the plant, thus killing the vine borers inside. You need to apply this weekly.


5) What cause squash fruit to fall off plant prematurely?

Aborting of fruit in squash is actually more common than you would think, and caused either by poor growing conditions or poor pollination. In the case of poor growing conditions, this is normally too much heat or not enough water or even a combination of both. Remedying the stressor will normally fix the fruit drop problem. Poor pollination can happen if there is a lack of pollinating insects in your garden. Simply adding more flowering plants to the area can help. A lack of male flowers can inhibit pollination too. Often they produce an abundance of male flowers early on, which fall off. The female flowers then have no male flowers, or very few, to pollinate them. Hand pollinating can help with this.


6) How to hand pollinate squash plants?

If you’re having issues with pollination of your squash plants, then it is sometimes necessary to hand pollinate the flowers in order to get fruit. This is achieved by locating a male flower, which will have a plain stem under the flower and an anther inside. Use a cotton swab or small paintbrush to gather pollen from the anther. Then transfer this to the stigma (raised orange structure) inside the female flower. Repeat this as necessary per flower. That’s all there is to it.


7) How to keep pests off squash plants?

Squash plants can be affected by a number of pests, most of which can be prevented through adequate care in the garden as well as practicing crop rotation. That being said, neem oil is the most effective pesticide you can use, and it even doubles as a fungicide should any fungal issues come into play. Neem oil is safe to use on all types of plants, including edible ones.


8) How to tell when squash is ripe?

When a squash ripens normally depends on the type of squash you are growing. For example, most summer squash is ready to be picked while still young, around 6 inches long or wide. Winter squash, however, are used when fully mature, meaning the best time to harvest is at the end of the growing season, right around the time of first frost. Other indicators of a winter squash that is ready to pick is to tap on it gently. If it feels solid and sounds slightly hollow, then it is ready to be picked. If pests or other issues threaten your winter squash crop, you can go ahead and pick the unripe squash and bring indoors to ripen. While this isn’t foolproof, it doesn’t hurt to try.


9) Should you prune squash plants?

You can prune squash plants some, but just a little. Remove only growing tips so as not to leave large wounds that may draw squash pests and disease. The growing tip is simply new growth located in the tops of plants. These can be pinched or snipped (nipping) from the plant to produce a more compact growth habit or inhibit spreading. Pinching off the tips of squash runners (after fruits have started to form) will allow the plants to spend more energy producing squash.


10) Why are leaves turning yellow on squash plant?

Yellowing leaves in squash plants could be due to either over watering or under watering. It could also be a lack of nutrients. They should be getting at least 2-4 inches of water a week, but there should not be standing water around the plants. If you have not fertilized and did not amend the soil at the beginning of the season, some additional nutrients may be helpful. Other reasons for yellowing leaves may be pests or disease.

We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We’re always here to help.

This article was last updated on
Read more about Top 10 Plant Q&A
Did you find this helpful? Share it with your friends!

Browse Dozens of Our FREE Gardening Guides Today

Whether your dream garden is a houseplant sanctuary, a bountiful vegetable garden, a pollinator paradise, a bright and bold flower bed, or a backyard oasis – Gardening Know How has the perfect gardening guide just for you.

Click the button below to access more than 3 dozen of our completely free and completely comprehensive guides to growing your dream garden.

Join Us - Sign up to get all the latest gardening tips!