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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 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

21 Nov 17, Hannah (New Zealand - temperate climate)
Hello, I am new to growing vegetables in general, and am really enjoying it. I recently planted three courgette plants, and did as instructed on the label which was to plant on a raised bed. They are not looking 100% happy at the moment, drooping a bit and some of the leaves are bit burnt/brown around the edges. I was wondering on some good tips for growing courgettes? And how often I should be watering them? Thanks. H
26 Apr 17, Maree (New Zealand - sub-tropical climate)
Can you sucessfully grow zuchini plants in containers, and if so, how deep + wide should the container be for one plant please?
26 Apr 17, John (Australia - temperate climate)
Yes you can. I have done it but the biggest challenge is to keep them moist enough so you don't get any setbacks. I used 400 mm (16") diameter plastic tubs.
05 Apr 17, Aloese Lefono (New Zealand - temperate climate)
Can they still grow and produce from April on?
07 Apr 17, John (Australia - sub-tropical climate)
By April, zucchinis and other members of the Cucurbit family (pumpkins, cucumbers, etc will be starting to die off. You may get a few more days that will ripen some of them but you are probably better to remove them and plant cabbage, cauliflower, etc or prepare the soil for broad beans. Check the page for your climate zone for other things to plant.
21 Dec 16, Dianne Lovell (New Zealand - temperate climate)
Any benefit in removing the lower grown leaves. The thing is a triphid
02 Feb 17, Karen (New Zealand - sub-tropical climate)
I agree with John. For powdery mildew prevention and control I use a brew of 3tablespoons of baking (bicarb) soda, 1/2 teaspoon non detergent dish soap to 6litre of water. The soda changes the ph and destroys the spores, soap acts as sticking agent. MUST test spay, leave 24-48hrs observe for chemical damage. May need less soda. Do not add anything to brew like fertiliser or neem oil, as this will change the ph and the brew will either become ineffective or cause damage. When ok with mix, spray everything (plant, container, soil, stakes etc) all over. Give sprayer a good shake prior and during application. Don't pour leftover brew into soil - ph change can cause growth problems of young plants. I do this weekly from planting out regardless of need; this minimises powdery mildew starting up. My cucs, courgettes and toms get this treatment but the amount of soda required may vary. I keep a note of the brew(s) and results for future reference. Best done in the evening so it has time to do its thing overnight without the risk of sunburn. Make a fresh batch of brew for each spray session. Remove some additional leaves to enable good ventilation throughout plant. What variety of triphid are you growing?
24 Dec 16, John (Australia - temperate climate)
The only benefit that I know of would be to increase air circulation and reduce mildew problems. If you are plagued by powdery mildew mix up a spray of 10% milk with water and thoroughly spray your plants. I can't explain why but it works. Trust this helps.
14 Feb 13, Al (New Zealand - sub-tropical climate)
I started cucumbers and courgette plants at the right time, but both plants have plenty of female flowers - no male flowers 3 months later. Don't tell me I do not know the difference, I am 88 years old and have been growing them since a boy in 1938. I moved to a new home 12 months ago. The pH where they are growing is 6.0. This has me puzzled. Thanks.
18 Jan 17, Te Pi' (New Zealand - sub-tropical climate)
Hello Sir, I was just reading through the comments further on, and it occured to me that you may have some micro-climates at your new property making things alot cooler/dryer/warmer- outdoor thermometer reads in the area for the day will tell you, and most likely the nutrient balance/microorganisms population is a lot different than your old place...I read somewhere that some squash or pumpkin can change their flowering habits due to a combination of level of nutrients/metals available and plant hormones in the soil, returning to male and female on seperate plants, maybe test the soil for nutrient levels and contaminants if you havent done so already. Is the seed your own or bought? If its not your own seed, you could take it up with the supplier, keep detailed records of these kind of issues and welcome questions about oddities etc, sometimes they purposely breed plants as F1 hybrids so you have to buy more seed to make collecting it not worthwhile
Showing 1 - 10 of 20 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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