Zucchini is an ideal plant for the beginner vegetable gardener because it is quick and easy to grow. Zucchini or courgette (Cucurbita pepo) is closely related to cucumber, watermelon, pumpkin and squash. There are also many ways to use the prolific fruit.

Planting schedule

Warm: April – September except for arid areas where September is the best.
Temperate: September – January
Cool: October – January

In temperate and cool areas it is best to sow seeds in small pots (try making them out of newspaper) indoors or in a greenhouse since they do not like cold weather. They usually germinate in 1 – 2 weeks and can be planted when there are several true leaves. In warm areas, direct sow seeds.

Position

Find a sunny spot with at least 6 hours of sun per day. It is best that they are sheltered from wind since their large leaves can catch the wind and cause damage to their soft stems. In exposed locations a trellis or some other form of support will be needed.

Because zucchini plants are large and sprawling, leave about 50 – 60 cm between them. You might sow seeds or plant seedlings closer and then thin them out to the desired spacing.

Talking Dirty

Like most fruit and vegetables, zucchini like good well-draining soil – raised beds will provide appropriate drainage or plant on a slight mound of soil.

Feed Me

Add plenty of compost or aged manure a week or so before planting and then again when flowering starts.

What about the water?

Since the fruit are very fleshy, zucchini need plenty of water – irrigation 2 – 3 times per week or a thorough deep hand watering once per week. It is important to avoid watering the leaves, especially late in the season when mildew and other diseases can be a problem. Don’t worry if the leaves wilt on very hot days – they will recover as long as the roots zone is watered regularly. Mulching with pea or lucerne straw will help keep soil moist.

Are we there yet?

Zucchini have separate male and female flowers and, like most species, it is the females that product fruit. The male flower grows directly on the stem of the plant in the leaf axils (where leaf meets stem) on a long stalk, and they are slightly smaller than the female. The male flower grows directly on the stem of the plant in the leaf axils (where leaf meets stem) on a long stalk, and they are slightly smaller than the female. Inside the flower, females have a rounded stigma whereas the male has a long stamen with pollen on the outside.

This is important to recognize if you find that flowers are forming but they bloom and fade, with no fruit growing afterwards. It could be that your garden lacks pollinators especially in recent years when bee numbers have been declining. If this occurs, you could try hand pollination. Use a fine paint brush in the mornings and carefully brush it against the male stamen and transfer pollen to the female stigma.

Planting other flowering plants, especially nasturtiums, which are a good companion plant for zucchini, will help attract bees to your garden.

Fruit usually appear 5 – 8 weeks after planting. Zucchini need to be regularly harvested to encourage continuous cropping. They are usually harvested quite small and immature as allowing them to continue growing results in fruit that is too big to be used as a vegetable. So watch carefully since once they start appearing since they can grow rapidly producing large unwieldy fruit. It is best to harvest when they are around 12 – 20 cm long.

The flowers are also edible – this is a good way to use the occasional excesses of male flower.  They can be used in salads, as garnish, and even fried or stuffed with cheese, bacon, mushroom or tomato and baked.

Pests and the rest

Few pests cause serious problems for zucchini but, like all Cucurbits, they can be susceptible to a range of fungal diseases. In particular, powdery mildew, but this is easily eradicated. Another potential problem is blossom end rot, which isn’t a contagious disease, but is caused by calcium deficiency.

Varieties

Zucchini are available in a range of shapes and colours, not just the familiar dark green sausage-shape that is readily available in supermarkets, but yellow, striped in different shades of green and even curved or almost round. For example, ‘Blackjack’ is a prolific bush variety with very dark-green long fruit, and ‘Golden’, is a yellow-skinned variety. A number of seed suppliers stock a variety of heirloom varieties that are worth investigating, including ‘Crookneck Early Summer’, which is very suited to those who aren’t able to harvest fruit as frequently, as they remain an edible size for much longer than other varieties.  There are also more compact varieties, such as Cocozelle, which means you don’t need to provide support or have a large garden space.

Information sources:

Yates Garden Guide, 42nd Edition, 2006, published by Harper Collins Publishers.
Blazey, C., The Australian Vegetable Garden – what’s new is old, 2001, published by New Holland Publishers.
Wikipedia