Zucchinis are related to pumpkin and squash and are one of the most prolific summer vegetables to grow. The vines have large green and mottled leaves with slightly prickly stems.

Most varieties produce narrow, dark green and slightly ridged fruit such as the popular ‘Black Jack’ and ‘Black Beauty’, but there are variations. Striped grey and green forms include ‘Greyzini’ and ‘Costata’. ‘Lebanese’ is a small, roundish, pale grey green zucchini. There’s also a golden variety called ‘Golden’.

Zucchinis are usually cooked and served in savoury dishes or as an accompaniment to meat, chicken or fish. They are packed full of beneficial nutrients including Vitamin A and C, potassium, folate and fibre.

Follow our seven easy steps to successful zucchini harvest including tips along the way.

Seven handy tips o how to grow tasty yummy zucchinis How to grow vegetables - zucchinis Handy Hints

When to plant and location.

When to plant.

Zucchini can be grown in most parts of Australia. Check with garden centres and hardware stores for varieties available in your local area.

In cool and temperate climates, zucchinis grow through the warmer months. Sow seeds and seedlings in spring (after frost has passed) and in early summer.
In subtropical zones, plant seeds and seedlings from August until January.
In tropical areas plant seeds and seedlings in April to September.

Location.

Grow in full sun or with light afternoon shade in hot climates.
Select a position that’s sheltered from strong summer winds that can damage the large zucchini leaves.
Zucchinis can be grown in beds, mounds, raised vegie beds or large containers or pots where garden space is limited.
Companion plant with herbs such as dill, mint or oregano, or try nasturtiums or marigolds.

Soil.

Get the soil right to harvest a bumper crop of delicious, yummy zucchinis.

Follow our steps for easy soil preparation.

Provide fertile, well-drained, slightly acid to neutral pH soil.
In areas of poor drainage, grow zucchinis in raised garden beds.
Dig in Seasol Super Compost or well-rotted manure before planting or apply Seasol Liquid Compost.
A soil rich in nutrients helps build strong plants so add Seasol Plant + Soil Booster (100g per square metre) and a fertiliser such as PowerFeed Controlled Release Tomatoes & Vegetables.
Water in well and let the soil rest for week or two if possible.

Step 1 – Sowing seeds.

The large seeds can be direct sown or started in punnets if the soil is still cold or there is likelihood of late spring frost.
In the ground, seeds should be sown directly in well-prepared, moist soil. Sow seed in shallow rows about 2cm deep and 70-80cm apart, pressing the seed firmly into the soil and lightly covering it.
In punnets, sow seeds in shallow rows into Seasol Seed Raising & Cutting Potting Mix and cover with seed raising mix.
In pots, choose a pot that is 40-50cm across and grow one plant per pot. Direct sow seed or plant seedlings, firming the small plants into the potting mix.
Water in well with Seasol GOLD or Seasol as this will help to increase seed germination rates. Soil should be moist but not wet, so check soil moisture daily to ensure zucchini seeds have the right conditions to germinate.

Step 2 – Germination.

Keep the soil or potting mix moist for the 7-14 days, as it can take this long for the first leaves to appear.
Germination is faster in warm soils, so if the weather is still cool, move seedlings to a sheltered position.
When zucchinis sprout, they only have two leaves. These leaves are known as the seed leaves, as they serve to access stored nutrients in the seed, feeding the young seedling until the true leaves develop and begin photosynthesising.
Water gently and apply Seasol GOLD or Seasol weekly (Mix 30mL of concentrate per 9 litres of water) as this will help to stimulate strong root development and healthy growth.
Check young seedlings daily for pests that may like to eat them and cover where necessary to protect them.

Step 3 – Baby zucchini seedlings.

About two weeks after the seed leaves have opened, the true leaves will appear; these are the first zucchini leaves.
If overcrowding occurs, select the strongest seedling and thin out or transplant the rest.
Use scissors or tweezers to thin out seedlings to avoid disturbing young roots.
Liquid feed with PowerFeed PRO Series for Tomatoes & Vegetables weekly to keep hungry seedlings growing strong and healthy. Mix 20mL of concentrate per 9 litres of water (standard watering can) for young seedlings.
Check soil moisture daily and water as needed.

Step 4 – Planting out zucchini seedlings.

Where plants are grown from seedlings, transplant with care after the first true leaves form.
Space 70-80cm apart and firm into the soil. To reduce stress, grow seedlings in biodegradable pots to plant directly in the soil.
When transplanting from seedlings that have been purchased follow the directions for planting on the plant tag.
In exposed locations, a trellis or some other form of support will be needed to protect young seedlings.
Apply Seasol to reduce transplant shock and aid plant establishment and promote healthy, strong growth.

Step 5 – Zucchini plant growth.

Keep plants well-watered especially on hot or windy days as these large, leafy plants can wilt when moisture stressed.
Remove weeds as they appear as they compete for space and nutrients.
Mulching around each plant suppresses weeds and helps retain soil moisture.
Every 6-8 weeks apply another application of PowerFeed Controlled Release Tomatoes & Vegetables to produce a bumper crop of tasty zucchinis and to revitalise depleted soils. Remember to water it in thoroughly after application.

Step 6 – Zucchini flowers & fruit growth.

Expect flowering within six to nine weeks. Fruit forms soon after the flowers appear.
Zucchinis have separate male and female flowers on each plant and both are needed to form fruit. The male flower is held on a narrow stem and its centre contains pollen-coated stamens. The female flower has a small swollen base, which forms the fruit after fertilisation.
Fruit forms after bees and other pollinating insects carry pollen from the male flower to the female flower.
Each plant crops for six weeks or more. Flowers are also edible but harvest excess male flowers so as not to reduce fruit harvest.
Feed hungry plants with PowerFeed PRO SERIES for Tomatoes & Vegetables weekly. Mix 50mL of concentrate per 9 litres of water.

Step 7 – Zucchini harvest.

Pick zucchini daily while the fruit is small (10-15cm long) and tender.
Cut fruit from the vine with a sharp knife.Regular harvesting keeps plants producing more fruit.
Search through the leaves for fruit as any that are left, even for a day or two, quickly turns into large marrows.
Keep zucchini plants healthy by removing dead and diseased leaves and stems. This will also open up air circulation around the plant.
Use on harvest day or store in the fridge in a plastic bag

Things to watch for…

Mildew This disease attacks zucchini leaves late in the season. The leaves will die back. If the harvest is nearly over, simply remove diseased plants. Avoid watering foliage especially late in the day. Mildew is also kept under control by a natural predator, a yellow and black spotted ladybird that feeds on powdery mildew.
Leaf-eating or 28-spotted ladybird A round orange ladybird with lots of dark spots. This ladybird skeletonises zucchini leaves but rarely damages fruit. To control, squash egg clusters and juveniles.
Pumpkin beetle A small, elongated orange beetle that also skeletonises zucchini leaves but rarely damages fruit. Squash to control.
Aborted fruit Small, immature fruit may yellow and fail to develop. This may be due to blossom end rot (a lack of calcium exacerbated by erratic watering) or lack of fertilisation if bees or male flowers are scarce. Improve watering. Warm weather as the season progresses usually solves any problems with fertilisation but female flowers can be hand pollinated using pollen from male flowers.