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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 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
    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 Feb 18, Peter Wilson (New Zealand - temperate climate)
How can I tell when my zuchinies are ready for picking
04 Feb 18, Quarteracre Kiwi (New Zealand - temperate climate)
Hi Peter - Leave them as little or as big as you like. If you pick them when they are about 25cm long, they will be lovely, fleshy and seedless. If you leave them past this point, they will quickly become marrow, which are watery and full of seeds. Give them a twist and they will come off with a bit of stalk. They will keep for a good while in your veg chiller of your fridge. If you get lots, you can grate them and freeze them in ziplock bags for winter. Give them a squeeze in a teatowel after thawing though.
30 Jan 18, thabo mofokeng (South Africa - Summer rainfall climate)
My babymarrows are rotten from inside. Thee past two years I never experienced any problems. They do not show from the outside that they are rotten inside some have worms inside. Pls advise. Thabo
13 Jan 18, John Bass (New Zealand - temperate climate)
re the question of 17 December. Tips of new courgettes turn yellow and then die back. Cause and treatment please.
08 Jan 18, Tony Barnes (Australia - temperate climate)
Planted my zucchini early in raised beds. Brilliant start looked good producing well. Then these and later plantings have started well but the leaves get a shrivelled look around the edges and only male flowers are produced. When I pull these plants out the roots are quite rotten looking. Am in Northern Rivers area NSW so very humid with warm/hot winds.
09 Jan 18, Mike (Australia - sub-tropical climate)
Try growing from Sept - as you say hot and humid now.
26 Dec 17, Steve (Australia - tropical climate)
All about the soil, my plants are the size of seven week old plants. Try a mix of compost, coir, perlite and tomato mix.
16 Dec 17, Nikki (New Zealand - temperate climate)
I am having trouble with my courgette. It starts off green and healthy, then the end gradually turns yellow which spreads up the the vegetable then it goes soft and shrivels up and dies. Do you know what's wrong? Thanks
30 Dec 17, Kay Rooderkirk (New Zealand - temperate climate)
We are having the same problem with out courgettes, I have green and yellow planted. We are in the Wairarapa, they have been grown in the same ground with NO problem. They have been watered with liquid horse manure, planted in soil enriched with mushroom compost. The new leaves seem to be Ok at the moment. The air temperature has been hot and cold. Thank You
05 Feb 18, Quarteracre Kiwi (New Zealand - temperate climate)
Some of my zucchinis used to do this too. I find if they grow on the ground they are more susceptible to this, so I lay pea straw around the base of my zuccs, and under where the growing fruit lies. This has helped. Another thing that helps is not watering the plant from above, but only watering at the base, so I have drippers on mine. My best zuccs this year are in a planter box, and they hang over the side. I have propped the plant up, so the fruits hang down in mid air. They are doing great and I haven't had any rotten ones grow on this plant at all. Another thing to consider is whether they are unfertilised ones that grow a bit and then die. Pumpkins do this. Make sure the flowers are accessible to bees, and I wonder if that's why my propped up one is doing the best of all.
Showing 1 - 10 of 257 comments

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.

- 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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