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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

15 Jan 19, Julie Sutherland (New Zealand - temperate climate)
We planted a yellow courgette and it is producing courgettes however they are white and not yellow - every other year we have had no problems....why might this be happening?
18 Jan 19, Julie Sutherland (New Zealand - temperate climate)
We planted an actual plant from the nursery... never ever had an issue before nd the people at the nursery assured me they do not have white courgettes....we were wondering if it was a climate thing or maybe a soil issue of deficiency...
25 Jan 19, Mike (New Zealand - sub-tropical climate)
If it is a hybrid it might be a throw back to a parent.
16 Jan 19, Mike Logan (New Zealand - sub-tropical climate)
Are they from the same packet as last year? Could be a mix up of seeds in the packet. I ordered boy choy last year and received Chinese cabbage.
21 Dec 18, Quent (New Zealand - temperate climate)
Do courgettes need trimed like tomatoe plants?
02 Jan 19, Mem (New Zealand - temperate climate)
Its a good idea to trim and leaves that are showing signs of powdery mildew (powdery white spots) or damaged leaves,other than that its not needed.
24 Dec 18, Mike (New Zealand - sub-tropical climate)
They are a vine so let them spread out or up a trellis. Tomatoes are a tree and don't have to be trimmed.
17 Dec 18, Laraine wright (New Zealand - sub-tropical climate)
If a courgettes grows into a marrow when is it ready to pick.
18 Dec 18, Mike (Australia - sub-tropical climate)
You pick it, the size you want. An example is - zucchini 3 to 8-9 inches . Marrow 12-18
27 Oct 18, (New Zealand - cool/mountain climate)
When planting seeds, which end of the seed should be facing the surface?
Showing 1 - 10 of 48 comments

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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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