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                  
      T                
      P P P            

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

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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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24 Aug 20, Dave (USA - Zone 9b climate)
I cannot seem to get my zucchini to grow. The leaves keep wilting and dying off and so do the sprouts from below. We have a raised compost garden with tomatoes and bell peppers. It has been VERY hot this summer so perhaps I should be watering more? At what times should I water to help the plants the most? Thank you in advance.
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25 Aug 20, Anon (USA - Zone 9b climate)
Take a look at the top of the page at the monthly planting guide, plant Feb Mar April. A lot of vegetables are seasonal so plant at the right time to get the best results. When watering, water low on the edge of the plant not above the flower and do it in the morning. A good watering 3 times a week.
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27 Aug 20, Dave (USA - Zone 9b climate)
Thanks! I'll follow that guidance. I suppose I might have to replant in the Spring then too :)
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10 Jul 18, Teri (USA - Zone 6a climate)
Should I cut back to make flowers to make females produce more?
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