By Steve Willis of Urban GreenSpace
So you have a balcony that gets good sun – at least five hours per day all year round – and is fairly sheltered from wind? Great. You can grow a citrus tree or two.
There are many considerations for growing fruit trees, so I want to warn you now that it takes a little lovin’!
- Reliable water but dry feet
Especially when in bloom, your citrus will need water up to three times a week. Make sure it isn’t sitting directly in water in the saucer – get some ‘pot feet’ if you need to. When growing any plant in a pot, make sure the soil never completely dries out. When completely dry, soil repels water meaning the water will drain straight through. If it does this, you’ll need to fully submerge the soil to take on water again, which isn’t easy if it’s a huge pot.
- Choose a pot with a decent surface area
There are many different shaped pots in various sizes and colours made from lightweight materials. Do some homework but remember you don’t need to settle on the final pot if you are buying a younger specimen. If opting for a narrow one, I recommend choosing a pot with a decent surface area such as a tall oblong rather than a narrow tall square – this will allow the plant to develop feeder roots.
- Choose the right plant
Many dwarf citrus and even grafted citrus feature different varieties on the one plant, such as orange, lemon, lime and more. Dwarf plants will grow full-sized fruit but the tree will only grow to about two metres high. If you have slightly less sun, such as four to five hours, or dappled sun, consider the Australian Finger Lime. I could write a whole article on plant selection, but I’ll just say make sure the plant hasn’t become root-bound. It may look good above ground but there may be many problems below.
- Decide whether you want an advanced or a young specimen
Once you’ve decided on the variety, you have an “advanced versus younger specimen” decision to make. For instant impact, you want an older plant but it will cost you a fair amount of money. I liken transplanting to moving to a foreign country. If you are young you will adjust and pick up the language and culture much easier than if you are a grown up. So too, a plant must readjust to a new location, microclimate and culture. You’ll find a younger plant will overtake a mature specimen in a few years and be more productive at a fraction of the price.
- When planting look at the plant and see which way it’s ‘facing’
Particularly with an advanced specimen, the plant will have leaves facing north so make sure you orient it the same way when potting it at home, then water with seaweed extract.
- Use the best possible organic potting mix
Speaking of culture, make sure you use the best potting mix you can find – one with a high mineral content so it doesn’t slump in the pot. Slumping will happen in mixes high in organic matter. This will cause compaction, squashing the oxygen out of the soil around the roots, which is bad.
- Make sure you plant the tree to the same level as it was in the pot you bought it in
Also, place a piece of geotextile fabric, available at most garden stores, in the bottom of the pot to stop sediment escaping and making a mess on your balcony (or your downstairs neighbour’s).
- You can underplant or mulch
Underplant. That means plant or cultivate the ground around the tree with smaller plants such as Mediterranean herbs or perhaps chives or just use mulch. This will help retain soil moisture. But make sure nothing touches the stem as citrus is prone to collar rot.
- Espalier your tree
Another cool thing you can do to make the most of the space on your balcony is to espalier your tree – this means to grow it on a flat plain such as against a wall on a trellis. When done well it can look fantastic, get creative with the pattern.
- Protect your tree from pests and diseases
Spray every two weeks with Eco Oil (or a homemade equivalent) to prevent most pests. Also use a liquid seaweed solution every couple of weeks. This isn’t a fertiliser, but a tonic. Fertilise in late autumn with a natural product such as ‘blood and bone’ and boost it with potash. Be careful not to add too much nitrogen as it will lead to a flush of new growth, which pests will find irresistible.
- Monitor and check
Keep an eye on the leaves. Are they lustrous and firm? Or are they soft, discoloured or crinkled? Are there swollen parts of the stems? These are signs of deficiencies and pests. Check the soil for moisture, and do a quick pH test. If the leaves are discoloured, do an internet search describing the pattern of discolouration (there’s not enough space to explain it here). Otherwise ask me in the comments below or tag me in a pic of the problem on instagram. I know it might sound like a lot of work, but once it’s established, providing a little shade, habitat and fresh fruit, it will all be worth it!
Keep an eye on the leaves. Are they lustrous and firm? Or are they soft, discoloured or crinkled? Are there swollen parts of the stems? These are signs of deficiencies and pests. Check the soil for moisture, and do a quick pH test. If the leaves are discoloured, do an internet search describing the pattern of discolouration (there’s not enough space to explain it here). Otherwise ask me in the comments below or tag me in a pic of the problem on instagram.
I know it might sound like a lot of work, but once it’s established, providing a little shade, habitat and fresh fruit, it will all be worth it!
About Steve Willis
Steve Willis is a designer, horticulturist and permaculturist but he likes the term ‘sky farmer’ due to his work with balcony and rooftop gardens. He works to make the urban environment a livelier, healthier more productive place by designing and installing edible gardens for restaurants, corporations and homes. Follow Steve in social media at Facebook, Instagram or Twitter
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‘Ask a green thumb’ is a new column for Green Villages. Our resident ‘green thumbs’ will be answering a reader query each month. If you have question, email us at email@example.com and we’ll find the best answer from our network of professional horticulturalists, permaculturalists and foodies.