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Growing Zucchini, also Courgette/Marrow, Summer squash

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

(Best months for growing Zucchini in New Zealand - cool/mountain regions)

S = Plant undercover in seed trays T = Plant out (transplant) seedlings

  • 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 1.5m 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

27 Oct 18, (New Zealand - cool/mountain climate)
When planting seeds, which end of the seed should be facing the surface?
27 Oct 18, Cesare Stella (New Zealand - cool/mountain climate)
I never bothered, I just lay them down
17 Oct 18, Gill (New Zealand - cool/mountain climate)
I have sown 2 sorts of courgette. The older seed (Italian) germinated as normal. The new seed purchased this spring has done nothing (the common yellow). At this stage seed pots are indoors
23 Oct 18, Mike (New Zealand - temperate climate)
Check to see if the seeds have rotted or not. Maybe they need a little sunlight to germinate.
19 Sep 18, Bess (New Zealand - temperate climate)
Is it advisable to pinch out the growing tips to stop the plants from getting too big? Thanks!
20 Sep 18, Mike (Australia - sub-tropical climate)
NO!!! The longer it grows the more zeeks you pick.
12 Oct 18, Mike (Australia - sub-tropical climate)
I have plants that are 5-6' long and still bearing zeeks. i want to pull them out but a fellow at the men's shed keeps hand pollinating them and they keep producing fruit. They are 5.5 months old.
06 Apr 18, Gaynor (New Zealand - sub-tropical climate)
How can I grow zucchini’s in Auckland in the winter thanks.
09 Apr 18, mike (New Zealand - temperate climate)
I don't believe you can grow them during winter, maybe with a good glass house and heater but you'd also probably need to hand pollinate.
04 Feb 18, Peter Wilson (New Zealand - temperate climate)
How can I tell when my zuchinies are ready for picking
Showing 1 - 10 of 39 comments

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.

- Quarteracre Kiwi

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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. GardenGrow 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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