squash end rot

Asked July 5, 2020, 10:52 AM EDT

I have had zucchini and squash blossom end rot for two years now. now spraying with a foliar calcium water mix. will this fix the problem? Besides adding lime before planting, are there more mid season solutions I should consider

Benton County Oregon

1 Response

Hi and thanks for contacting Ask an Expert.
Do you rotate your plants? If you have not, rotate your plantings next year. If you plant in containers, add composted manure when you plant. If you have a disease in a pot, empty it out and clean it with a 10% bleach solution and then add fresh soil.
Do you use organic compost as a soil amendment? Organic matter contains many of the nutrients needed in your vegetable plants and should be used regularly.
I am making the assumption that you have not added lime to the soil as yet from the way your comment is worded. The zucchini that has blossom end rot will not become normal. Remove them, However, getting the lime into the soil, may help the future zucchinis to develop normally.
Another question is how much nitrogen have you added? Too much nitrogen will produce great big green leaves but not much fruit and it can stop the plant from absorbing the calcium.
Check your soil pH level as well. There are inexpensive test kits at most nursery stores. The soil should be between 6.0 to 7.0 or basically slightly acidic to neutral. Follow the directions on the package. If it is too acidic, the calcium you are adding in the agricultural lime will sweeten the soil or bring up the pH level. I definitely recommend adding the dry ag lime to the soil.
Water on a regular basis, not letting the soil completely dry out. Adequate water also helps the plant take up the calcium. Use a mulch such as straw around the plants to keep the soil moist.
You might want to take the liquid calcium and apply it under the soil to the roots as well. Plant metabolism systems run nutrients up from the roots as well as down to the roots from the leaves. This gives the plant the opportunity to absorb it both ways. Many experts recommend foliar sprays, others say put it in the soil for the roots.
I am adding a link from Clemson University on planting and growing squash. Scroll down to Cultural controls to read about blossom end rot.
https://hgic.clemson.edu/factsheet/summer-squash/ If you have further questions, please contact us again. I hope your plants recover.