Q.
Hi, we are growing about 10 different citrus including oranges. The oranges all seem to be quite sour. I have sprinkled Epsom salts around - is that going to be enough to help? Also, how can I stop the fruit and leaves getting black scum on them? Thanks, Leah.
A.
The black scum is sooty mould, there will be insects – aphids, scale, mealy bug on the tree. Spray (with warm soapy water, or check at your local garden centre for a suitable spray) to control the insects and the sooty mould will go away. Sweetness of oranges can be affected by a variety of factors including climate (needs some warmth to sweeten), variety (some being more sour than others), ripeness (try leaving them on the tree a bit longer). To help grow successful oranges make sure you feed them in spring and summer with Tui Citrus Food and keep them well watered. Add a layer of mulch around the base of the plant too.
Q.
Hi, my lemon tree has plenty of lemons on it but no leaves. What could be causing this? Thanks, Amy.
A.
Citrus are evergreen but do drop leaves, usually when they are stressed, too cold, have too much fertiliser, or not enough fertiliser, if there’s frost, or they are too wet. I would suggest regular doses of Tui Organic Seaweed Plant Tonic every seven days until the tree starts bursting into leaf. Give it regular feedings in spring and summer when temperatures warm up. Don't feed it in winter as the tree isn't actively growing. Try adding sheep pellets to nourish the soil and mulch around the tree so it doesn't dry out in summer. If it is in a pot and become pot bound it might need re-potting.
Q.
I have several citrus trees. I've been told that in the first year of fruiting, I should remove all the fruit from the tree. In the second year, I should remove half of all the fruit from the tree (when it is the size of a 20c piece), and in the 3rd year I should remove 1/3 of the fruit. Is this good advice? Thank you, Caroline.
A.
It’s definitely a good idea to remove the fruitlets off the tree in the first year. The subsequent years, the rule of thumb you noted is a good idea in theory, but it does depend a lot on the health, strength, size and type of tree. In general terms of fruit thinning, you want to remove a portion of the crop so that when the fruit is mature, each fruit is not touching the next (as this can cause blemishes and disease problems). You also need to take into account the weight of the fruit on the branches, so that the mature fruit will not cause breakages. So after the first year, it really is a judgement call as to how well the tree is establishing, how heavy the crop is and how much the tree can handle.
Q.
I moved house and the place we are in now has a mandarin tree. The mandarins are tiny, what can I do to make them grow bigger? Thank you, Joanne.
A.
Mandarins are wonderful fruits. For the crop this year there is nothing you can do to remedy the problem. In the spring, give the plant a side dressing of citrus food and add a layer of mulch all around the base of the plant. This will feed the plant and keep the root zone moist. Over summer keep the plant well watered, small fruit indicate poor watering over the summer when the fruit develops. An application of Tui Organic Seaweed Plant Tonic now will give the plant a boost, but avoid adding the fertiliser too early as young growth may get frosted.
Q.
Hi, I got a lemon tree a few months ago. Its leaves are curling and dull. I've given it citrus food and haven't noticed a change. What do you recommend? April.
A.
Citrus leaves will curl when temperatures are cold or in extreme heat, some insect infestations such as scale, mealy bug, mites or aphids will cause leaves to curl or over-watering. We have had unseasonably cold weather.
Adjust watering depending upon the weather. Feed it Tui Organic Seaweed Plant Tonic plant tonic regularly, keep it well watered if it is heat, or just give it Organic Seaweed Plant Tonic regularly if cold and watch the watering, don’t over-water it. Feed with controlled release fertiliser(suitable for containers) in early spring and late summer. In frost prone areas avoid feeding any later than mid February as this will push soft new growth that will frost easily and won’t have had time to harden off.
If it is an insect problem control common insect pests by spraying warm soapy water, or check at your local garden centre for a suitable spray. If ants are crawling up the tree then there is a good chance there is scale insect or mealy bug or aphids.
Q.
Why is citrus food not suitable for use in containers? Thanks, Margaret
A.
We generally don't recommend using our Food range (including Tui Citrus Food) in pots and containers because it is not a slow release fertiliser and can overfeed in a smaller space e.g. pot or container, especially if not applied in the correct amount. This will then affect the plant. We recommend a controlled release fertiliser such as controlled release fertiliser for use in pots and containers.
Q.
My lemon tree has heaps of lemons which don't have any juice. Do you know why this is? Thanks, Pauline.
A.
Dry lemons are normally caused through lack of water over the summer period as the fruit is forming. You can't get the moisture into your current seasons lemons but you can fix the problem so it doesn't happen next year, by watering more regularly. It can also be caused by lack of fertiliser. Now is the right time to apply Tui Citrus Food around the base of the plant then again at the end of fruiting, add a layer of mulch around the base of the plants after you fertilise to help the soil retain moisture. For citrus in containers, we recommend using controlled release fertiliser.
Q.
Hi, can you tell me why my limes keep dropping off my tree. I get loads of flowers and most of them start to form little limes and then all of a sudden I lose most of them. I water every second day and also feed it. I am growing it in a large pot. Pam.
A.
Fruit drop is caused by stress – water (too much or too little), temperature (hot/cold extremes), nutrition problems and/or pest/disease problems. Some things to consider:
- How long as the tree been in the pot? It may need repotting, to replenish the growing media as it can become ‘hydrophobic’ – which means the mix actually repels water. Use good quality mix like Tui Pot Power.
- Have you fed the tree enough? For citrus in pots you need to take care to use a suitable fertiliser. Citrus are heavy feeders so need very regular fertiliser to keep the leaves dark green and glossy (no yellowing, curling or discoloured veins), with lots of new growth and fruit production. Use controlled release fertiliserfor citrus in pots, or Tui Citrus Food for trees planted in the ground.
- Are you watering deeply enough? There should be enough water applied that it leaks steadily from the drainage holes in the pot, so that the growing media is well drenched. Check the moisture levels on the day you don’t normally water by poking your finger down into the dirt. If it’s damp it doesn’t need more watering that day, but if it’s dry, you may need to move to daily watering.
- Is the tree exposed to cold snaps? Cover with protective cloth or move into a warm area if unseasonal cold spells/nights are expected.
Q.
The leaves are turning yellow on my mandarin tree. I have tried feeding with citrus food and worm castings, do you have any other ideas. Thanks, Jacqualine
A.
If magnesium is deficient then the leaves will turn yellow. Your tree will benefit from a dose of Epsom salts which is magnesium. Use Tui Epsom Salts. Also make sure your tree is free from weeds which will compete for water and nutrients and mulch around it to help conserve soil moisture as well as keeping weeds down.
Q.
Hello, I have a lemon tree that has lots of fruit but the leaves are covered in yellowish nodules and they are crumpling up. The fruit is flavoursome but the outer skin is looking like a case of tiny acne with thin brown lines. What do you recommend? Thanks, Rachel.
A.
The lumpy fruit and distorted foliage is caused by a fungus disease called verrucosis. It is prevalent in citrus and by spraying the tree when it has finished flowering with copper oxychloride until it starts to bud and flower will help prevent the disease.
The damage caused by verucosis is largely cosmetic. The fruit flavour is fine, and the fruit usually juicy. As the disease distorts the foliage there is reduced plant vigour but it generally doesn’t kill a plant. Regular feeding with Tui Citrus Food, watering and mulching will help the tree become more resistant to pests and diseases. Regular applications of Tui Organic Seaweed Plant Tonic will also be beneficial to your tree.
Q.
Just wondered if you have a nice way to get rid of the ants on my citrus trees but not disturb other insects like the bees! Thanks Maureen
A.
Fortunately, the ants do not harm the fruit, they are there because there will be an insect exuding a honey dew such as scale, aphids, or mealy bug. By controlling these insects you should not attract ants. Check at your local garden centre for a suitable spray - there are natural options available.
Q.
We have an orange tree in our backyard but the oranges never ripen properly, they never turn orange and when cut open they are pretty well tasteless and mushy. What could be the cause of this please?
A.
Oranges require a long warm summer and mild winter to fruit successfully. If your climate is right, the most likely reasons for the lack of fruit is the plant isn't getting enough nutrients from the soil. Fertilise in spring and summer with Tui Citrus Food. It would also be useful to prune back your orange tree to encourage some new growth and fruiting wood. The more air movement and sunlight the plant can get the more likely the fruit will ripen. Water frequently in summer as this is when the fruit is developing its flavour and size.
Q.
Hi, my lemon tree is looking lovely and lush with green leaves and new growth after giving it a dose of citrus food. It's two years old and had two blossoms when I bought it. Once planted, the fruit dropped off when they were only about 1cm long, and it hasn't blossomed since. Do you know why? Thanks, Vicky
A.
As the plant is only two years old it is not a problem that it is not flowering as it is good for the tree to spend energy in establishing its roots first. We suggest feeding with Tui Citrus Food or controlled release fertiliser in early spring and late summer to assist with flowering.
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