Growing Zucchini, also Courgette/Marrow, Summer squash

Cucurbita pepo : Cucurbitaceae / the gourd family

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

(Best months for growing Zucchini in Australia - tropical regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • 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 21°C and 35°C. (Show °F/in)
  • Space plants: 50 - 90 cm 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
  • b) Six or seven weeks old
  • Zucchini flower

Plant into a slightly raised, well composted bed and mulch. Needs regular plentiful water. Produces large leaves with a spread of about 1.5 m x 1.5 m. 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. If there are no bees around and the fruit are not setting well or die off after starting to grow, try picking a male flower (straight stem) and gently brushing pollen inside female flowers.

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 5 gm/teaspoon Bicarbonate of Soda in 600 ml/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 15 cm / 6 inches.
Pick frequently to keep the plant producing new flowers.

Your comments and tips

Post a comment or question Display Newest first | Oldest first, Show comments for Australia | for all countries
10 Feb 24, paul swan (New Zealand - temperate climate)
why does the young growing marrow/zucchini go brown or rot on the flower end of the vegetable before maturity.
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14 Mar 24, Harry (New Zealand - temperate climate)
Hi Paul, blossom end rot can also be associated with water issues and/or calcium issues. Sometimes the plant suffers because water is too unreliably available, i.e. it dries out between adequate waterings. The growing zucchini will be
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15 Feb 24, Liz (New Zealand - sub-tropical climate)
Rot in young flowers usually means that they have not been pollinated. You might have to try hand pollination
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21 Jan 24, Michael (Australia - arid climate)
Hey guys 2 questions if somebody can help , I have 5 zucchini plants all looking healthy had a few fruits yet am having many smaller yellow zucchini, I am hand pollinating in the mornings yet these turn yellow before the flower opens Second question Have Black eggplant plants , quiet large lots of flowers yet not a single fruit yet Any tips for a novice gardener ? Thankyou
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01 Sep 23, Elaine (USA - Zone 9b climate)
I tried growing zucchini in raised beds this summer. Followed all the instructions here. They produced 2 or 3 fruit per plant then started dying. Yellow leaves, soggy stems. Maybe I over watered? I gave each plant about a litre of water per week. It’s also been very hot (90F+ constantly from the beginning of June) When you say plenty of water, how much is plenty?
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03 Sep 23, BaltimoreHopeDealer (USA - Zone 7b climate)
The most likely culprit was squash vine borers. They bore into the base of the stem and eat the plant from the inside. You will notice that the leaves aren't getting nutrion and will turn yellow/brown. Production will slow down and the roots will start to get squishy and gross. Finally, the plant will fall over and die.
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17 Sep 23, Michele (USA - Zone 9b climate)
I had a really bad issue with aphids this year. Killed all my zucchini and cucumbers. Can we plant in September in Zone 9b?
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19 Sep 23, (USA - Zone 9b climate)
Best to wait until February/March/April
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23 Sep 23, Anonymous (USA - Zone 9b climate)
Thank you!
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02 Sep 23, Naomi (USA - Zone 9b climate)
Hi Elaine, I had a similar problem this year with my zucchini. The plant never grew much, and didn’t produce any fruit. The temperature was very high 105s for the peak growing time in my area. I am have my fingers crossed we will get a few squash before it gets cold. I am going to try and plant mine early next year and hope they get started producing before the heat sets in. Post if you find an info about plants not producing. Cheers. Naomi
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Dolomite lime. It's a good source of calcium. For some reason the link in my previous reply was deleted.

- Fred

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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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