Zucchinis are one of the easiest and most rewarding vegies to grow. They can grow in garden beds, raised beds or in large pots and containers. If growing on a balcony or patio, look for compact varieties as the traditional forms need room to grow. Zucchinis are fast growers, only taking between six to eight weeks from seed to harvest and with the right care, one plant can yield between 3-4kg of fruit! Here’s how to grow zucchini.

Position

Like most fruiting plants, zucchinis need at least six to eight hours of direct sunlight to grow well. If hot conditions are expected, erect a shade cloth or use a large umbrella to protect their delicate leaves from the hot afternoon sun.

Soil

If planting in the ground, ensure the soil is moist and well-draining. Dig in plenty of compost and aged manure and fork in well. For pots and containers, choose a large container – at least 40cm deep and wide – and fill with a premium quality potting mix.

Planting

You can sow seeds or plant seedlings. While seedlings will give you a head start, zucchinis are fast growers, so even from seed they only take 6-8 weeks to mature. Follow the sowing or planting directions on the label, water in and mulch well with an organic mulch like sugarcane or pea straw. 

Fertiliser

Once flowers appear, feed regularly with a liquid fertiliser that’s high in potassium – this is needed to encourage prolific fruiting. If unsure, look for a fertiliser specifically formulated for flowering and fruiting. 

Water

Water regularly to keep the soil moist. When watering, water the soil as much as possible instead of the leaves. Fungal issues can occur when water sits on the leaves for most of the day. 

Maintenance

As plants grow, they like to sprawl out. If you don’t have the space, train zucchinis to grow up a lattice or similar support structure. 

Harvest

The flavour is best when picked young, usually when they’re approximately 10cm long. If you find you’re being inundated with fruit, remove a few of the flowers and fry them up with garlic and oil or stuff and bake them.  

Troubleshooting

  • Powdery mildew: Zucchinis are highly susceptible to powdery mildew. This fungal disease causes a white powdery film to grow over the surface of the leaf, and if left untreated, can affect the overall health and vigour of your plants. To help reduce the risk of fungal issues, avoid watering the leaves and ensure the plants are spaced well apart. If treatment is necessary, spray with an organic fungicide like eco-fungicide. 
  • No fruit: Zucchinis have both male and female flowers. For fruiting to occur, pollen from the male flower has to successfully transfer onto the female flower. Pollinating insects like bees and butterflies can help with this, but if there aren’t many insects around, you may need to give Mother Nature a helping hand. Use a small artists brush to collect pollen (fine yellow powder) from the male flower and dust it onto the centre of the female flower. If you’re wondering which flower is which – the female flower has a swollen base that resembles a small fruit. 

Varieties to try:

  • Rondo de nice: compact variety with small round fruit.
  • Greyzini: unusual grey-green striped fruit, ideal for growing in large pots.
  • Blackjack and Black Beauty: classic zucchini varieties with large dark green fruit. They are ramblers, so ensure you have the space for them to grow. 
  • Goldrush: beautiful golden-yellow fruit, perfect for containers or raised beds.