Hi Tui, my lemon tree which is 4 yrs old has yellow leaves, help! What do I do to stop this?
There are a number of reasons why your lemon tree leaves could be turning yellow. The most common cause it a lack of magnesium in the soil. Epsom Salts helps correct magnesium deficiency, mix 30g of Epsom Salts per litre of water (approximately 2 tablespoons), per tree. Alternatively, Epsom Salts can be applied directly to the soil at the same rate, water in well after application.
Citrus need regular feeding, use a specially blended fertiliser such as Tui Citrus food. Feed citrus twice a year, in early spring (once the risk of frost has passed) and again in late summer. Water in well after application. If you are in a frost prone area make sure you don't fertilise too late into autumn as this will push soft new growth that doesn't have time to harden off before winter and is at risk of frost damage.
A few cultural tips for growing citrus that may be useful are plant in a frost free sunny position. Make sure the soil is free draining with plenty of organic matter in the soil. Regularly water throughout the summer months. Mulch around the tree in early spring to help conserve soil moisture, to add organic matter to the soil and suppress weed growth. Tui Mulch and Feed is great for citrus as it has blood and bone as well as a blend of pea and lucerne straw to add organic matter to the soil.
To help boost overall plant health, apply Tui Seaweed Plant Tonic to citrus regularly at a rate of 30ml per 9L watering can every 4-6 weeks. Seaweed helps strengthen the cell wall of the plant and protect it from temperature extremes, hot and cold. This needs to be applied around 6 weeks before frost is expected to protect from frost, it will still be of benefit to the plant if it is applied now.