Our indoor Lisbon Lemon tree that we bought 2 months ago has slowly been deteriorating and we've tried everything! It is placed in the SW corner of the house, surrounded by windows, and gets tons of light. I'm a faily amateur gardener and cannot figure out what is wrong with it! We have special citrus fertilizer that is has had once, and we spritz the leaves at least once per week. The leaves immediately curled up (see images) when we brought inside, and some have small holes in them (I don't know if this is related). We trimmed back and cleaned up the inside a bunch because we thought the interior wasn't getting enough light, but that failed to do anything. Now the leaves are turning a bit yellow. The soil on top (see image) is also very hard and dry and impossible to penetrate (this is new). I tried to aerate this morning. Overwater/underwater? Both? This morning I discovered the soil at the bottom was drenched and quickly removed excess water, and now I'm worried about root rot. Help! What are we doing wrong? I feel so bad for this poor tree.
You may have several problems at the same time. The tree may need repotting, but do not increase pot size too much-- 1 to 2 in increase in diameter of the pot. When you slip the plant out of the pot -- look at the roots-- if they are firm and tan/cream colored --that's fine--if they are brown and spongy --that's root rot and should be removed carefully. The tree needs fertilizer-- once every 3-4 months if you use slow release fertilizer, more often if you use soluble type. Trace minerals should be added if they are not in the fertilizer. Do not water unless the soil is dry at least 2 inches deep. When repotting, use a potting soil that drains well--without too much peat moss. Skeet
If you purchased a healthy Lisbon Lemon tree only two months ago, the problem is in the container. I noticed the tree is sitting in a water collecting basin. Either get rid of the basin, or NEVER let ANY water remain in the basin, even for a short time. The growth medium at the bottom of containers will always contain a much higher concentration of water than the rest of the medium. This area is called the Perched Water Table, and it is commonly wetter. The two most important, and required, substances in the root zone of the tree are water and OXYGEN. Approximately 25 to 30 percent of the growth medium should be air. If it was my tree, I would first check the root system. Healthy citrus roots are a light cream/tan color, and if the roots are actively growing the root tips will be white. If the tree is suffering from root rot the roots will be a chocolate brown and mushy. A citrus tree with curled wilted leaves such as your tree is displaying, can be caused by over watering, resulting in root rot, caused by the lack of oxygen more than the over watering. However, leaf curl and wilt can also be caused by the lack of enough water throughout the root zone. *IF*you do not see any root rot I would set the tree in a bucked of water containing one teaspoon of dissolved citrus fertilizer per gallon and let the tree soak until the entire root ball is thoroughly wet. Lastly, citrus trees are heavy feeders, and should be fertilized at least once a month at approximately 250 PPM Nitrogen. Millet Anthony van Leeuwenhoek 1632 - 1723
