I once read a survey in an Australian landscaping magazine that listed the top five things you could expect to find in the average Aussie backyard – they were: a barbecue; a Hill’s Hoist (washing line); a dunny (outside toilet); a dog and a lemon tree.
It tells you a lot about Australians and their way of life – and that gardening is not top of their list! However, I’m fortunate that my life as a horticulturist in Australia has been full of gardens and wonderful gardeners, and their passion for citrus trees is evident (not just the lone self seeded bush lemon tree!). Citrus are always top of the clients’ ‘must have’ list and questions about citrus always outnumber any other gardening questions.
In previous posts about citrus I have discussed pruning and planting, caterpillars on citrus and how to deal with common pests (scale, sooty mould and aphids).
Lastly, I’m going to tell you how to recognize nutritional deficiencies in your citrus trees and what their feeding requirements are. When it comes to giving citrus tender loving care there are a few basic principles – one of the most important is adequate nutrition – CITRUS ARE HEAVY FEEDERS.
WHEN: Citrus have very shallow surface-feeding roots and require fertilizing three times a year in July, November and March. This is particularly important in areas of heavy rainfall where the soil rapidly becomes depleted of nutrients. That’s why it is also important to mulch them out to the drip-line to minimize soil run off and help maintain the nutrients in the soil.
DON’T feed the soil while they are in flower otherwise you will have a lot of leaves and no fruit.
DON’T OVERFEED – especially with nitrogen or you will end up with a lot of overlarge and thick-skinned fruit.
WHAT: Citrus are heavy fruiters and take up a lot of the essential macro and micro nutrients out of the soil – they require the lot LITTLE and OFTEN. Potassium (potash) is essential for flowering and fruiting and a natural constituent of seaweed – that’s why regular feeding with a compost tea, that contains seaweed, or a seaweed concentrate is a good option for citrus. I would recommend the following mixed with 4.5L water for the three times a year feeding regime. Water in this mix around the drip-line of the tree – that is where the feeder roots are.
- 3 tbs seaweed concentrate
- 1 tsp trace elements
- 2 tsp iron chelates
Iron – a common deficiency in citrus with dieback of the new growth and intra-veinal mottling of the leaves.
- Choose an open and sunny spot to plant them – out of the wind.
- Mulch out to the drip-line.
- Feed regularly – not forgetting the essential trace elements.
- Prune to shape regularly.
- Ensure they are getting adequate water – particularly when the fruit is setting – dry plants mean dry fruit.