Do you have citrus planted in pots?  Are you concerned that they are not getting enough nutrients or water?

I have grown citrus in pots since I first started food gardening in 2007, I have accumulated quite a few tips for growing citrus in pots.  I have had quite successful crops over the years, and am not having too many problems.

Lindsay from the very informative blog, treadingmyownpath.com asked me via email about nutrients, pots types, and soil amendments.

She asks;

Hi Gavin,

I’d love your thought on fruit trees in containers. I moved two weeks ago and finally have a balcony, so have bought some fruit trees and pots to get it all started. Now my experience of growing is in the UK but now I live in Perth WA – two very different climates! So I’d like to hear what you did, please. Did you just drill holes in the pots, stick the trees in with some soil and pretty much leave them to it? Do you fertilise – if so how often?

I have a Eureka lemon and a Tahitian lime, and two half wine barrels to plant in, and I’ve bought some decent soil and manure. The guy at the shop reckons I should be adding something to the soil every 8 weeks but I don’t really have the budget or the space for a ton of soil amendments! So if you could tell me what you do and your yield (estimated if you don’t know) that would be helpful! Also, how do you find watering them in summer? Do you use retic or water by hand?

Sorry for such a long question! Any advice appreciated! : )\

Well Lindsay, thanks for your question.

Citrus trees grown in pots are pretty easy to look after.  As you live in Perth, then probably best to keep them in the barrels as the soil is fairly sandy and doesn’t hold a lot of moisture.  Similarly, here in Melton, I plant in pots because our soil is rock hard clay.

Fertilising

I fertilise once every quarter (3 months) with a handful of blood and bone, and half a about a quarter of a cup of dolomite lime (for the calcium and magnesium), both scattered around the top of each pot.  Then I water this in, and then add a thin layer of compost.

This keeps them fed for the three months.  I kind of time it when they flower in spring, and fruit in late autumn.

Pots and Microclimates

The pots are about 48cm in diameter, and 55cm tall, which are glazed black.  I figure that this keeps the root ball warm in winter and it is why I get such a great crop of lemonade, mandarins and limes.  Four of the pots are located up against a wall running north and south, so it heats up during the day providing a sheltered and warmish microclimate for the citrus trees.  The other four are around the swimming pool which provides heat in winter and additional reflected light.

These pots are fairly large with the soil coming about ¾ full (with the tree inside.  This is so I can add the organic fertiliser and compost.  There is also a hole in the bottom about 3cm in diameter.  When I potted it up, I placed broken crock over the hole, added about 10cm of premium potting mix then placed the tree’s root ball on top.  I then backfilled with more potting mix and watered in well.

Watering

I have four of the eight trees included in my irrigation system so this helps a lot during summer.  However, I do find that I need to water at least once a day during the really hot weather (40°+) to keep them thriving.  In winter, I water weekly to make sure they are moist.

Now here is a citrus secret that you won’t read everyday.  I also add human urine to a 9 litre watering can (about 500 ml of wee), and give quarter of the watering can to each tree.  On a good day, manage to get around to all 8 trees.  They love the extra nitrogen and acidity of this liquid neutralises the alkalinity of the dolomite lime.  I do this once a month.

Nutrient Deficiencies

If you ever have a problem with yellow leaves with green veins through the leaf especially on new growth, but the soil is moist, the tree has an iron deficiency.  The soil is too alkaline and the tree cannot take up iron from the soil.  You need to add iron chelate, or do what I do and place rusty nails in each pot.  These also add iron to the soil over time.  I don’t normally get this issue due to watering with the wee solution each month.

Look carefully for mottling on the leaves of plants because this is an indication of magnesium deficiency, which is really common in Australia.  The easiest solution is to get some Epsom salts (Magnesium sulfate).  Take half a litre of water, and put in half a teaspoon of Epsom salts, then shake and stir. Either water it on plants or you can foliar spray it.  The mottling will go after a week or two.

Another issue to look for is yellowing of the leaves.  Yellowing does occur naturally in winter, however if you see it in summer then it is a potassium deficiency.   When you buy the blood and bone make sure it has added potassium (potash) and you shouldn’t get this problem.   However, if you do see it, correct it with adding soluble potash; use half a teaspoonful in 4.5 litres of water, stir that thoroughly and apply it at the roots.  Do this every two weeks until the leaves regain their colour.

Fruit

After about 3 years of loving care you should see fruit appear in abundance.  If fruit tries to set in the first two years, I would highly recommend knocking it off just after it has set.  The tree needs to grow strong before it can handle the task of growing fruit and is usually able to handle a full crop of delicious fruit after about 3 years of growth.

I do keep our trees under 2.5 metres with light pruning after the harvest.

Depending on the tree, I usually get more fruit than I can eat and find that we even give some away after a few weeks.

 

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Hopefully this post has answered all the questions, and now all readers who live in temperate climates will be able to grow this fantastic source of vitamin C.

If anyone has any other tips for growing citrus in pots, feel free to leave a comment.  The more tips the better!