How to Grow Zucchini

Zucchini seeds are quick and easy-to-grow vegetable seeds, perfect for all vegetable patches. Famed for their large harvests, if you know how to grow squash, then zucchinis (or courgettes as they are known elsewhere) will be no problem, and you will be supplied with a consistent haul of tasty and versatile vegetables throughout the summer. Learn all that you need to know about growing zucchinis here at Mr Fothergill's.

Learn everything you need to know to grow zucchini seeds from when to plant zucchini to the best time to harvest them, so you can enjoy fresh-grown zucchini to level up your meal times.

Zucchini Classification

Group: Squash.

Family: Cucurbitaceae.

Zucchini Seed Varieties

There are several different varieties of zucchini that grow worldwide and here in Australia. They come in various sizes and a myriad of colours, including all different shades of green and bright yellows. Some of the varieties you can find at Mr Fothergill’s include:

Goldrush

Greenskin

Lebanese

Midnight Container

Black Beauty (organic)

Striato d'Italia (Johnsons)

Zucchini seeds enjoy full sun coverage, so be sure to choose an area of your veg patch that gets at least six hours of sunlight each day. To have the perfect soil for sowing your zucchini seeds, you should ensure the soil is well-draining and enriched with organic matter. A soil pH of around 6-7 is ideal for zucchini.

Weed the garden bed thoroughly, adding in manure or compost until sowing. Wait for the right conditions, and then sow your zucchini seeds!

Zucchini seeds should only be planted once the soil has warmed up, and there is no risk of frosts that could damage the plants. For most regions in Australia, you should plant your zucchini seeds in spring through early summer. For colder regions, waiting for the risk of frost to pass is imperative, even if it means waiting longer. Warmer regions can benefit from the milder winters and plant their zucchini seeds as soon as early spring.

How to Sow Zucchini Seeds

For the best growing conditions, wait for the soil to have warmed to 20 degrees or more before you sow your zucchini seeds. If the soil is too cool, the seed may fail to germinate, or worse, rot, so if the conditions aren’t right, be sure to start the process indoors with tool accessories like a heat pad to keep the soil at the right temperature.

In most areas, spring is the perfect season for squash vegetables like zucchini seeds. Sow the seeds directly 12mm deep and 60cm apart, with rows separated by 80-120cm. Plant your zucchini seeds with small mounds of compost and organic fertiliser-enriched free-draining soil. Keep the seeds moist to germinate, which should take 6-10 days. Your zucchini plants can be allowed to trail or be staked to allow for better airflow.

Where to Plant Zucchini Seeds

Plant your zucchini seeds in a location that will see at least six hours of sunlight every day. 

How to Grow Zucchini Seeds

Just like squash seeds, zucchini seeds are hungry and need plenty of nutrition as they grow. Apply a balanced slow-release fertiliser once the plant is around 5cm tall. Every 4-6 weeks, you can side-dress with an additional feed. Keep the plants well-mulched to retain the most moisture, and remove any weeds as you go. 

Water regularly targeting the root zone, keeping the leaves dry, and as the plant grows in size, prune off any side shoots to keep the plant on one stem, making it easier to harvest. You should allow your zucchini plants to trail or stake them to allow for better airflow to the plant. 

Hand Pollinating

Zucchini seeds produce both male and female flowers, with the female flowers producing the zucchinis. It can be easy to spot the difference between the two, with male flowers having a thin stem and female flowers producing immature fruits at the base. To hand pollinate, pick the male flower, peel back the petals, expose the central pollen and then brush the pollen into the centre of as many female flowers as you can find.

As well as hand-pollinating your zucchini plant, zucchinis are also pollinated by multiple different pollinators, such as bees or even ants so don't be alarmed if you see ants visiting the flowers!

Remove Leaves

Removing older leaves from the plant will encourage new growth and also improve the air circulation reaching the plant. Getting rid of the older leaves can also help to alleviate issues such as powdery mildew and squash bugs. 

Pests & Disease Advice

Numerous types of pests and diseases can threaten your zucchini plants. From pests that target seeds to diseases that, left untreated, could kill the plant, learn how to prevent and, treat diseases and pests.

Pests

Slugs and snails are pests every gardener has come across. The slow-moving gastropods just love to feast on young zucchini seedlings. If you find them an issue, you can apply an organic slug pellet during the germination process to remove any threat whilst the seedlings grow. As well as pellets, there are also natural defences you can put in place, including surrounding the seedlings with a barrier. You could use something as simple as eggshells to protect the seedlings from pests.

Diseases

Zucchini plants are particularly prone to diseases such as powdery mildew. Plants typically succumb to mildew at the end of their growing season while still producing plenty of fruit. To prevent mildew, keep the leaves dry when watering or even water the plant in the morning, allowing the leaves to remain dry throughout the day. 

Staking the plants will help improve airflow and reduce the risk of powdery mildew. Another way to improve airflow to the plant is by pruning the lower leaves, which will also remove spores. If the plant is still young and afflicted, an organic fungicide spray will do the job.

Companion Plants

Zucchinis have plenty of options for companion plants that can be grown alongside your zucchini seeds. You can find a wide variety of companion planting seeds at Mr Fothergill's, including:

Bean seeds

Herb seeds, including parsley and oregano

Flower seeds such as Borage and Nasturtium work well with zucchini seeds too.

You can rotate your zucchini crops along with other spring vegetable seeds, including cucumber seeds, and fruit seeds, such as melon seeds or pumpkin seeds. Take a look at our in-depth companion planting guide for more information on the best companion plants for zucchini.

Yellow flowers are an indication that your zucchini plant will soon start producing fruit. When the zucchinis have grown, be sure to pick them regularly, cutting from the main stem to keep the plant producing more. You will know a zucchini is ready when it measures around 20cm in length and the fruit has a glossy skin.

Zucchinis are best eaten freshly picked but will store for a short time in the fridge. They are also a popular vegetable to preserve by pickling or canning, they may also be frozen for longer-term storage.