Greetings, For fun, my son and I started a lemon tree from BIO lemons. The sapling grew and looks great, but sometimes the leaves turn brown from random places on the leaf. I grow this inside, with plenty of light, water and heat. Is there something wrong with my lemon sapling?
Lemon Tree Sapling
Certified GKH Gardening Expert
The first thing I notice is that there is quite a bit of dead, and uncomposted materials in the pot. These should be cleared out. I can't really see the soil composition underneath, but It appears that there is a severe pH imbalance. Foretelling of this is the wrinkled leaves. It also, likely, has a magnesium, calcium, and iron deficiencies because of this.
Now, you can correct these by simply adding dolomitic lime, and iron sulphate to the soil. Make sure to keep any dead plant material out of the pot, and make sure there are no walnuts buried in the soil. Make sure the soil does not contain any pieces of the shell or the nut, as these pose a problem for most soils. They are highly toxic to most other plants.
It is best to purchase citrus soils, if you do not have experience mixing your own soils for this purpose. I have mny container citrus of many varieties, and I can say that they take up a lot of time and resources to grow properly in this fashion. This tree will take some learning to get used to its care.
For now, here is an article that will help: https://www.gardeningknowhow.com/edible/fruits/lemons/growing-lemon-trees-containers.htm