The Secret to Success With Zucchini

14 May 2015, written by Ann Marie Hendry

The zucchini is one of the easiest vegetables for new gardeners to grow from seed - simple to care for, quick to grow, reliably prolific and endlessly useful in the kitchen.

Zucchini aren't difficult to grow, but it took me a while to get a really good crop, so it's worth taking time to ensure growing are conditions right. Believe me, it can be frustrating if every gardener you know is moaning about their zucchini glut when you've only managed to produce a few fruits late in the summer! Here are my tips to ensure a steady supply of zucchini.

Sowing Zucchini

Sow zucchini seeds on their side so that water easily drains off to avoid the risk of them rotting. Once germinated (which usually takes about a week, give or take a day or two), keep seedlings in a sunny position indoors until all risk of frost has passed, then harden them off to get them accustomed to outside conditions. Alternatively, sow them outside under cloches or horticultural fleece (row covers) if the weather is warm enough. Zucchini can't cope with cold temperatures, so don't start them off too early - check recommended sowing and planting out times for your location in our Garden Planner.

For zucchini to be highly productive they need plenty of fuel in the form of nutrients from the soil and sunlight to help them photosynthesise efficiently. It's best to plant them in a sunny part of the garden where they won't be overshadowed by other plants, in soil that has had garden-made compost or well-rotted manure added.

Personally I never seem to get as good a crop when growing in containers, although many people do grow zucchini (particularly compact varieties) successfully this way. I have to admit that I tend to neglect potted plants a bit! It is vital to keep on top of watering and feeding when growing in pots.

Keep cloches or fleece at the ready for cool nights. Water regularly if the soil is dry and mulch to minimise competition from weeds and to help retain soil moisture.

Male and Female Zucchini Flowers

When flowering starts, your zucchini plants will only produce male flowers at first. Why male flowers with no female flowers to pollinate? My theory is that this draws in insects such as bees who will return to the plants once the female flowers are produced, and this will enhance successful pollination.

You can make use of some of these male flowers by deep-frying them, though make sure you leave enough on the plant to ensure successful pollination. You'll know when your plants have started to produce female flowers, because female flowers have an immature zucchini fruit behind them, while the male flowers are produced on long, thin stalks with no such swelling.

Start feeding your plants with a liquid tomato feed or homemade comfrey fertiliser twice a month as soon as flowering begins, and continue to keep the soil well watered.

Zucchini Problems

One issue that is of significant concern is poor pollination. Zucchini need to be visited by a lot of bees or other pollinators for successful pollination, otherwise the fruits will abort. When this happens the fruits will stop growing, turn yellow and may start to rot. To avoid this make sure you include plenty of pollinator-friendly flowers in and around your vegetable garden, and avoid using any pesticides. Additionally, you can hand-pollinate the flowers - this may be necessary in wet summers when insect pollination is poor.

Stressed plants may also abort their fruits, so make sure you keep them well-watered and protect them with fleece or similar if the weather turns cold.

Cucumber Mosaic Virus (CMV) affects zucchini as well as cucumbers, squash, pumpkins and some other non-related plants. Zucchini affected by CMV will show mottled, puckered leaves, and the fruits will be distorted and bitter-tasting. Aphids transmit the disease, so keep populations down by growing plenty of nectar-producing flowers that will attract aphid predators such as lacewings, ladybirds (lady bugs) and hoverflies. You can also hose aphids off plants with a strong jet of water whenever you spot them.

Zucchini may also be affected by powdery mildew in hot, dry weather, which is fortunately simple to prevent by using a diluted milk spray.

Zucchini growing in the vegetable garden

Avoiding a Glut of Zucchini

The zucchini glut is well known not only to vegetable gardeners but to their families, friends, neighbours and casual acquaintances too! An over-abundance of vegetables is not a bad problem to have, but there are limits…

The trick to avoiding a glut of zucchini is to pick the fruits while they are still small - anything up to about 20cm (8in) - and to pick them regularly. Picking and eating some of the male flowers will also help to slow production.

Still, you're likely to have a steady supply of zucchini so it's a good thing they're so versatile. I like them best roasted along with other vegetables and added to pasta, but they can also be grilled, fried, baked, stuffed, grated into sauces as a thickener, sliced thinly into salads, or made into fritters or zucchini bread. Contrary to what some foodies say, you can freeze zucchini - they just go a bit soft, so if frozen are best used in dishes where the texture doesn't really matter, for example zucchini soup.

If you have any tips for growing a great crop of zucchini, or for using up a glut, we'd love to hear them - please share them in the comments below.