Notes by Phil Dudman
Whether on acreage, a suburban block or city courtyard, anyone can have a go at growing a few fruit. The great thing is it allows us to harvest when fruit are perfectly ripe, which means they taste better and are higher in nutrients. But it’s more than that; many fruit trees make wonderful shade and climbing trees, some are useful windbreaks and privacy screens while others are just a pleasure to look at.
What to grow
Here’s a general list of the types of fruits we can grow here in the northern rivers
Avocado, Banana, Blueberry, Citrus, Custard Apple, Feijoa, Fig, Lychee, Grape, Guava, Kiwi Fruit, Macadamia, Mango, Mulberry, Olives, Papaw, Passionfruit, Pecan, Persimmon, Pineapple, Pomegranate, Strawberry, Tamarillo, Tropical Apples, Stone Fruit
Where to grow
Fruit trees need six or more hours of direct sun a day. A north or north-easterly aspect is best. They need shelter too – strong winds can damage trees and upset pollination. Where necessary, allow space for building a fence or planting a windbreak. Try to position your fruiting plants reasonably close to your house. That way you are more likely to keep an eye on any problems that will require immediate treatment.
Preparing the soil
Most fruit trees tolerate a range of soil types. The important factor is good drainage. Poorly drained soils such as heavy clay are improved by digging in compost and gypsum. This helps clay to form a ‘crumb’ like structure that allows air and water to move more easily through the soil. Mounding improves drainage too and creates a greater depth of topsoil for root development. While sandy soils drain beautifully they dry out quickly. Adding lots of well-rotted compost and manures will help hold moisture for longer in sandy soils.
Soil pH is important too. All fruit trees perform better when they are grown in their preferred pH range. Generally, fruit trees grow best in a neutral to slightly acidic soil of pH 6 to 7. Some plants prefer a more specific pH range for example, blueberries must have a pH of 4 to 5 to thrive and olives perform best when the soil is slightly alkaline i.e. a pH of 7 to 8. Pick up a simple pH testing kit from your garden centre and test samples from across your growing area. If you need to increase the pH of your soil, use agricultural lime or dolomite and to lower pH use powdered sulphur.
Fruit trees need regular watering, especially during flower and fruit development. How much and how often depends on your soil type and climatic conditions. As a rule, one deep soaking a week is sufficient, but if your soil is sandy, you may need to water twice a week during hot or windy conditions.
Water the root zone: the area between the trunk and the outer canopy (the drip line) where the young roots develop. Avoid wetting foliage and flowers. Early morning is the best time to water. If you plant lots of trees, consider installing an irrigation system. This is the most efficient way to water trees and will allow you to automate this most important task.
Mulching fruit trees with straw, compost and animal manures conserves moisture, adds valuable humus to the soil, reduces weed competition and helps keep soil temperature even. Your trees will perform much better when mulched. Try to maintain a cover of up to 70mm thick around and beyond the drip zone. Don’t allow mulch to touch the trunk as this may encourage disease.
Regular fertilising with fruit fertilisers helps to provide the nutrients that fruit trees need to keep them growing and cropping well. Recommended fertilising times vary for different types of trees, so be sure to mark the months on your calendar.
See Katrina’s tips below on making a compost mesh bag for feeding your fruit trees.
Fruit in small spaces
Traditional fruit trees need a growing space of 3 to 5 metres diameter. Some trees, such as mangos, need more. While this may limit the number of trees you can grow in a modern backyard, there are plenty of space-saving ways to introduce variety.
An assortment of fruit of the same type can be grafted onto the one rootstock. With a multi-grafted tree you can grow lemons, limes, mandarins and oranges all in one space of just 3 to 5 metres.
These are high-yield selections that have been grafted onto a dwarf rootstock. This produces more compact trees that are ideal for planting in smaller spaces and in pots.
If you are really tight for space, try espalier. It’s the age-old practice of training trees flat against a wall or fence. All you need is some type of frame like lattice or wires that have been attached horizontally to a wall or timber fence. As the tree grows, horizontal branches are tied to the frame and anything growing outwards is pruned or shortened. You can train trees into all sorts of interesting shapes this way – limited only by your imagination – to make both an attractive and productive feature.
Growing in pots
When it comes to growing fruit in pots, dwarf trees and various berries are the most productive choices. Choose a big container at least 40-50cm wide and make sure it has adequate drainage holes – if not, drill some more. Plastic and glazed ceramic pots are better than porous terracotta pots because wind won’t pass through the sides and dry out the roots. Use only a good quality potting mix. It’s worth adding additional coir peat too so that the mix holds moisture for longer. Also, mix in 30 to 40 per cent coarse river sand to help avoid a big drop in the level of the mix over time.
Potted trees can dry out quickly so they may need to be watered regularly, up to twice a day in hot, dry or windy weather. Be aware, when potting mixes dry out, they can become water repellent, which spells disaster for plants. If this happens, block the drainage holes temporarily with clay (or something similar) and fill the pot to the top with water to thoroughly saturate the mix. After an hour or so, reopen the drainage holes to allow the water to escape.
Phil’s Top Tips
1. Choose a good spot – one with at least 6 hours full sun a day with good drainage and protection from strong winds
2. Prepare the soil well before planting – no matter what type of soil you have, fruit trees will benefit when you add lots of compost and mound the soil
3. Water, mulch and fertilise regularly – that’s the way to grow the juiciest and sweetest fruit while keeping your plants healthy and productive
Katrina Shields returns this week as our guest writer
How to make compost mesh bags for fruit trees.
Here is a simple and effective way of feeding fruit trees.
- Length of shade mesh to show how much is needed to make a bag
- Pre-sown mesh bags 25 cm wide and 50 cm long with an open end
- Garden or kitchen waste
- Established fruit tree
- Fill the bag with scraps.
- Fold over the end.
- Place under the mulch.
- Sprinkle a small amount of dolomite on the soil to encourage worms.
The worms will be attracted to the scraps and penetrate the mesh to eat the organic material. After the material is almost eaten, and the castings watered into the soil, it can be topped up and moved to another tree.