The Secret To Growing Healthy Citrus
Glenda Smith, a home gardener, shares her secrets to growing healthy citrus trees.
Glenda Smith - Guest Blog
23 September 2015
The Citrus family includes Buddah’s Hand, Chinotto, Cumquat, Grapefruit, Lemon, Lemonade, Lime and Kaffir (aka Makrut) Lime, Mandarin, Orange, Pomelo, Rangpur and Tangerine trees.
If you are short on space, select Dwarf varieties of citrus and/or a Citrus Splitzer which is two or more varieties of citrus grafted onto one root stock. You can also train your tree to grow flat against a wall or supported on a lattice. This is known as espalier.
They are ‘gross feeders’, meaning they require full sun, regular watering and regular applications of fertiliser.
Growing Citrus in Pots
If you are growing your citrus trees in a pot, select a deep, non-porous pot. Terracotta and clay pots will dry out too quickly if you are short on watering time. A deep pot will protect the roots from the heat, and if it is light enough to lift, can be placed into a deep water container for a few hours to save time and water. Although citrus love water they do not like their roots to be constantly wet so do not sit your pot in water 24/7.
During the summer months, citrus require deep watering at least one day per week around the dripline (the ground area at the outermost circumference of a tree canopy where water drips form and drip onto the ground). This is also the most effective place to apply your fertiliser so the roots can easily take up the nutrients.
Slow release fertiliser specifically formulated for citrus trees is the most efficient because it is a 3-monthly set-and-forget application.
TOP TIP: To remember when to reapply, apply at the beginning of each season or at the beginning of each quarter of the year.
The fertiliser is not only good for the tree and the fruit, but also the soil. Nematodes feed on plant roots and starve crops of nourishment, thus reducing the amount of fruit. Telltale signs are tumour-like growths on plant roots. They thrive in tired, spent soil.
TOP TIP: A natural way to deter nematodes is to dig a hole under your tree, place prawn shells into the hole and return the soil to the hole.
Pruning encourages your citrus trees to be strong, well-shaped and to fruit prolifically. Prune your tree at least once per year. Just remember not to prune when it is budding or flowering otherwise you won’t receive any fruit that year.
TOP TIP: Should your citrus be badly burnt by a severe frost, do not prune it until you are sure the frost season has passed.
Signs to look for about the health of your Citrus:
- If the leaves look shiny and firm, they are receiving enough water
- If the leaves look dull and limp, the tree is asking for water
- If the leaves are yellow, the tree is lacking iron
- If the leaves are yellow and have an inverted “V” in the leaf base, the tree is lacking magnesium. Use a tablespoon of Epsom salts dissolved in 9 Litres of water and water around the dripline of the tree and over the leaves
- If the fruit is splitting, it means the tree has received irregular watering.
Should Sooty Mould (a fungus) infect your trees, it is easily treated with a few buckets of grey water from your washing machine. Throw a bucket or two of grey water over the tree if it’s low growing, otherwise decant the grey water into a hand-pressurised bottle with a long spray wand to reach the higher branches.
Although fruit trees are susceptible to fruit fly, they can be controlled with traps and predators. Here are some options:
- Pheromone-based traps which attract the male-only fruit fly
- Protein-based traps which attract both male and female fruit flies
- Predatory insects and birds which feed on the maggots
- Attractants – the most natural and cost-effective solution
You can make your own attractant pest controller by one-third filling a plastic soft drink bottle with a vegemite and water solution, or beer, or a teaspoon of yeast in water. Add a few drops of washing up detergent to break the surface tension of the water. The pests cannot escape and drown. Make a small hole for the insects to enter near the neck of the bottle and hang it in your citrus trees. Empty and replenish the contents every 1-2 weeks.
TOP TIP: To prevent the spread of fruit fly, place dropped and stung fruit into your garbage bin, not your compost bin. Otherwise the pests will continue to breed. Have you ever opened a compost bin and had a swarm of bugs flying out? They will be fruit fly.
TOP TIP: When using pest oils to control scale and bronze/stink bugs, do not spray on the leaves in the hottest part of the day otherwise the oil will burn the leaves.
If you follow these tips, you should always have healthy citrus trees and prolific fruit.
If you would like to read more from Glenda you can visit her blog: Growing Snowballs
If you would like to write a guest blog, further information can be found here: Earn Yourself a $50 HOSELINK Voucher
N.B. This article has been written for Australian gardens. If you're reading this from around the world, we do hope you've found it a useful stepping stone for your own further research.
Pruning citrusHi Glenda, is there a correct way to prune a citrus tree, or should I just prune it to the size and shape that suits me?Ed Hauschild, 29 July 2016
Fruit treesFruit tree tips will be followed thank you. Also the cress egg delights are just the thing for the grandchildren and me CheersLaraine, 2 November 2015
Succinct and well writtena concise and easily followed brief on everything to help grow healthy citrusRoss Brown, 29 October 2015
Orange you helpfulI just got a mandarin and an orange tree for my birthday this month, so this is very helpful as it's my first try at growing citrus. Can't wait to reap the rewards.Chrissy, 28 October 2015
Very HelpfullTips are easy to understand and to the point........... GreatPeter Usher, 23 October 2015