Gardening Know How strives to provide the best possible information so your garden will flourish, regardless of what you’re growing. In the vegetable garden, zucchini squash is a popular plant but also one that includes its share of issues. Find solutions for common zucchini problems and how to grow healthy zucchini plants below with answers to the top questions about zucchini.
Zucchini plants grow quickly and ought to start producing fruit after about 45 days. If it’s been longer than that, and especially if your plant is producing and then dropping flowers, you have a problem. This is likely due to a lack of natural pollinators. Try cutting back on pesticides, as you may accidentally killing beneficial insects. Also try planting flowers that are known to attract pollinators around your garden. If worse comes to worse, you can pollinate your zucchini flowers by hand by picking the male flowers and rubbing them against the female flowers.
Zucchinis are famously prolific and ought to consistently pump out fruits through the growing season. If your zucchini plant has produced only a couple of fruits, something is wrong. The problem is most likely due to too much nitrogen in the soil. You can test your soil to confirm if this is the case. Unfortunately, getting rid of excess nitrogen isn’t a quick job, as it has to be leached out. The best way to do this is by growing plants in the area that soak up lots of nitrogen…like zucchini. Adding bone meal, which increases phosphorus levels may help offset the nitrogen. Later in the growing season, you might see a big increase in fruits.
If your zucchini fruits are turning yellow on their ends, you likely have blossom end rot. Once the rot sets in, the affected fruits are lost. You can take steps to prevent it from happening to future fruits, though. The main cause of blossom end rot is a deficiency in calcium. Feed with a fertilizer that’s low in nitrogen and high in calcium. You can also add gypsum, which is high in calcium, or use a calcium rich foliar spray. If your soil’s pH is too low, it will affect calcium uptake. Check your pH and add some lime if it’s below 6.0.
Squash borers are common zucchini pests, and they can devastate a plant virtually overnight. The best squash borer treatment is prevention. Don’t plant zucchini in the same spot two years in a row. If any plants fall victim to squash borer, remove them and don’t compost them. Apply pesticides to the ground at the start of the growing season to kill any larvae. Wrap the base of your vines in nylon to keep the borers from getting inside. Check for borers by shining a flashlight at the vines at night – they’ll block the light from passing through. Carefully slit the vine open with a knife to remove them.
Powdery mildew is a very common problem for zucchini plants. It’s a fungus that thrives in high humidity and damp conditions, so the best way to prevent it is to cut down on moisture. Don’t plant your zucchini too close together, and avoid damp or shady spots. Prune away dead or dying material right away. Avoid watering at night when the moisture will sit on the leaves longer without evaporating. An organic powdery mildew treatment can be made out of 1 part hydrogen peroxide and 9 parts water. Spray this mixture on affected plants once per week.
Dropping zucchini flowers is a very common occurrence, and not necessarily even a problem. Zucchini plants produce separate male and female flowers, and both need to be present at the same time in order for fruit to form. At the beginning of the growing season, a zucchini plant will often put out only male flowers to make sure there is enough pollen present for the later female flowers. These flowers will just fall off without forming fruit. If it’s still early summer, just give it time. If your plant has been dropping flowers for a long time, you might have to pollinate by hand.
Hand pollinating zucchini plants isn’t difficult, and it can yield a lot of fruit if it’s done correctly. The main thing to understand is that zucchinis have distinct male and female flowers. Only the female flowers will grow into fruits. If you look closely, you’ll see that a female flower has a small baby fruit on its stem, just underneath the petals. A male flower just has a normal stem. To hand pollinate, pick a male flower off of the vine. Gently rub its anther (the part inside covered with powder) against the raised orange part inside each of the female flowers.
Zucchini plants have distinct male and female flowers, and both are necessary for pollination to work. Luckily, they’re easy to tell apart. Female zucchini flowers come with a tiny squash already attached to the stem, just below the petals. After pollination, the flower will drop and the baby squash will swell into a full fruit. Male flowers don’t have this; they just have a plant stem under their petals. Male flowers are only needed for pollination and after blooming they’ll simply drop off the plant. This is why you’ll see flowers falling even from a healthy zucchini vine.
Zucchini is famous for producing huge fruits. Although those giant squash are edible (and very good stuffed and baked), the best time to harvest them is when they’re about 6 inches long. The flesh will be more flavorful and the skin less tough. These smaller fruits are excellent eaten raw, grilled or pan fried. Zucchini is very easy to pick. Just hold the fruit firmly and twist. The stem ought to snap right off of the plant. Zucchini plants are tough, so you don’t have worry too much about hurting them.
Zucchini plants attract quite a few insect pests like cutworms, armyworms, aphids, flea beetles, squash bugs, thrips…the list goes on and on. A lot of these bugs can be kept away simply by keeping the area clear of weeds and not too moist. If you already have a bug problem, however, it’s time to break out the insecticide. Neem oil is an excellent organic product that works wonders. It can be mixed in water and used as a foliar spray that breaks down extremely quick, which means it kills bugs on contact but won’t harm other animals. It can also be applied to the soil to be taken up by the plant and used to kill insects as they try to eat it.
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.