Gardening tips from Chris Davidson | Summer fruits in the Avon Valley

Related stories: Gardening in the Avon Valley.

The cucurbit family consists of about 965 species, however most of these are not commonly cultivated for consumption around the world.

The more commonly grown cucurbits you will find at your local fruit and vegetable markets are watermelons, rockmelons and pumpkins.

The heavy soils of the Avon Valley, warm summer temperatures and plenty of sunlight are perfect for these types of crops to thrive. 

The very low summer humidity and lack of interest from problematic pests like parrots and Mediterranean Fruit Fly also makes growing them easier.

Melons and Pumpkins are grown in large open areas where space is not a problem as the vines can grow quite vigorously.

They are susceptible to fungal diseases like powdery mildew and downy mildew in wet humid climates, however this should not be a problem in the Avon Valley over summer.

Overhead sprinkler irrigation is generally not a good idea as this will cause the fungal problems and waste a huge quantity of water. 

A simple approach of trickle irrigation is the preferred option.

The trick to growing a sweet rockmelon is to slowly wean the vine of water at the last stages of fruiting to encourage an increase in sugar content but not too much that the vine leaves are wilting, it becomes a balancing act gained thought experience.

The biggest problem in the Avon is the Calcium deficiency.  The red heavy soils are acidic and naturally low in calcium. 

This is a problem for fast growing cucurbits like zucchini’s if not treated.  Cucurbits require calcium for leaf development and if this requirement is not meet, the fruit will suffer with blossom end rot. 

The calcium issue is easily overcome with using crushed limestone (Calcium carbonate).  A cheap source of this is crushed limestone road-base from the Swan coastal plain ploughed into a cucurbit patch.

Another way of regulating the amount of fertilizer and calcium required is fertigation. This method is when a soluble fertilizer is pre-mixed into a drum before injecting into the main irrigation line. 

One soluble fertilizer used in the horticulture industry is Calcium Nitrate and is ideal for this purpose.

For a home backyard an application of general purpose fruit and vegetable fertilizer and trickle irrigation is more than sufficient to grow melons and pumpkins as they are a very easy crop to grow.

Irrigation requirements for watermelons (citrullus lanatus var. lanatus) can be confusing as many people think that huge amounts of water are required. 

This is not the case as the watermelon is native to Sub – Saharan Africa.  This is the same area where paddy melons (Citrullus lanatus var. citroides) are native to and you don’t need much water for paddy melons to thrive in the wheatbelt, any farmer will tell you.

I get asked from time to time how do they make a seedless watermelon seeds.  The process is accomplished by crossing varieties of fruit with different numbers of chromosomes. 

The process is complicated to explain but seedless watermelon seeds are generally sold to commercial growers and the seeds are grown in rows alongside seeded varieties for pollination.

Generally, one seeded row for every three seedless rows, the result is more seedless melons than seeded.  As seeded melons these days have no commercial value they are usually discarded.

I remember cutting a seeded water melon in half to show my young children as they have never seen one and their response was “Dad what’s all the black things yuk!”.

Cantaloupes or rockmelons are similar in water requirements. 

These melons are very susceptible to moisture rot where the part of the melon that sits on the ground.  This is the reason why all melon growers use plastic mulch to prevent it from occurring. 

Some black plastic garbage bags from the kitchen will suffice for the home gardener or even some spare ceramic tiles placed under the fruits.

Pumpkins are a very easy crop to grow but a simple pitfall for the home gardener is being impatient.  The crop only starts to ripen in May for a true pumpkin. 

However, the Butternut Pumpkin is a squash and can have ripe fruit much sooner and all through summer.

Happy Gardening….

Chris Davidson

Misty Ridge Plant Farm