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Growing Zucchini, also Courgette/Marrow, Summer squash

Jan F M A M J J A S O N Dec
    S P P P            

(Best months for growing Zucchini in USA - Zone 5a regions)

S = Plant undercover in seed trays P = Sow seed

  • Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 70°F and 95°F. (Show °C/cm)
  • Space plants: 20 - 35 inches apart
  • Harvest in 6-9 weeks. Cut the fruit often to keep producing.
  • Compatible with (can grow beside): Corn, beans, nasturtiums, parsley, Silverbeet, Tomatoes
  • Avoid growing close to: Potatoes
  • a) seedlings
    a) seedlings
  • b) Six or seven weeks old
    b) Six or seven weeks old
  • Zucchini flower
    Zucchini flower

Plant into a slightly raised, well composted bed and mulch. Needs regular plentiful water. Produces large leaves with a spread of about 1.5m x 1.5m. Some varieties trail a bit but don't climb. The yellow (or gold) variety is more resistant to mould damage in humid areas and remains productive even when the leaves have mildew on them. The yellow varieties sometimes have yellow patches on their leaves but it is just colour not disease.

Blackjack is the most popular green variety. At the start, the plants produce mainly male flowers. The female ones start as the weather warms up and the plants grow. A spray with a 5gm/teasp Bicarbonate of Soda in 600ml/pint of water will help slow powdery mildew when it appears.

Culinary hints - cooking and eating Zucchini

Zucchini are best picked or cut off the stem at about 15cm / 6 inches.
Pick frequently to keep the plant producing new flowers.

Your comments and tips

04 Dec 17, Robert (Australia - temperate climate)
I have 2 plants that are growing well, I have one zucchini that matured,but now the small fruit are turning yellow before the flowers open and fall off. Any advice please.
08 Dec 17, Fred (Australia - sub-tropical climate)
Mix one cup of milk to 2 litters of water and put 2 cups of the mixture into the base of each plant. And you need to use this lime sprinkle two hand full around the base of the plant before watering.
08 Dec 17, Fred (Australia - sub-tropical climate)
Dolomite lime. It's a good source of calcium. For some reason the link in my previous reply was deleted.
13 Dec 17, Mike (Australia - sub-tropical climate)
They don't post links.
05 Dec 17, Meg (Australia - temperate climate)
Mine are doing the same. From past experience I know that no fertilisation is taking place. Unfortunately the flowers are remaining closed so you can't even do it yourself!
07 Dec 17, Mike (Australia - sub-tropical climate)
I posted here in the pumpkin section - the female flower only opens one day and is shut by mid afternoon. So the bees or you have a very limited time to pollinate the female flower. Zucchini pumpkin cucumbers are from the same family so maybe this applies to all these plants. If you don't have bees then you need to look each day to see when the female flower opens. It takes approx. 12 visits by a bee to pollinate a pumpkin female flower.
05 Dec 17, Mike (Australia - sub-tropical climate)
Read through the comments here for zucchini, there are many about this problem.
22 Nov 17, Heather (Australia - temperate climate)
I have zucchini growing well but they are starting to go bad at the end where the flower is attached - this is when the flower has wilted but has not fallen off. Should I knock the flowers off when they have wilted?? many thanks for your advice
23 Nov 17, Mike (Australia - cool/mountain climate)
Try not to water around the flowers - water around the base of the plant. Your plants are probably not being pollinated by bees. Check to see if you have male and female flowers. You can pollinate by hand if no bees. Even some Epsom Salts around the plants may help. Read the other comments here.
25 Nov 17, Heather (Australia - temperate climate)
thank you Mike, I appreciate the advice
Showing 1 - 10 of 245 comments

Yep cut them.

- Mike

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. Gardenate is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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