Q. Frank, this is a variegated leaf pink lemonade lemon tree bought last December. The fruit you see were present when bought. You will notice there are several dropped leaves on the planting soil and I an eager to know what is causing them to drop. The tree is watered irregularly but last week I hyper-saturated the soil when I neglected to move the hose in a timely fashion.
Assuming the cause of the dropping may be insect related, the tree was sprayed two times in four days with neem oil. Now the question is what is causing the leaves to drop? Was it my one-time over-watering? A combination of the over-watering and the neem oil? Would the over-watering cause the roots to become waterlogged? Will the leaves eventually start to grow back?
I found the following bag of ‘garden soil’ with only a small quantity of content left in the bottom of the bag. This leads me to the assumption this is what I probably used potting the lemon tree. While I might have mixed it with some other remnant gardening product found around the garage, soil or mix, this product probably represents the vast majority of the what I used. Visually this garden soil looks similar to what is in the pot around the lemon tree. Hopefully this product identification addresses your question, resolves the issue and provides a reasonable platform for further discussions and a solution/conclusion to the continuing episode of “The Falling Leaves".
A. One of the most important components of potting soil is not the organic material, but the inorganic material that provides for drainage. Drainage is the word used to describe the soils ability to allow water to move through it. Media that is heavy in organic material prevents water from moving through it because there are few if any spaces for the water to travel, and a plethora of compounds and surfaces that actually cling to water (they are called hydrophilic compounds). This allows for a root-space that eventually becomes devoid of oxygen, a primary factor in root growth.
The substance in the bag that you have sent me a picture of is organic compost replete with lawn trimmings and table scraps. This product is fine to add to a garden where it is to be dug in and diluted with the sand, clay and silt that is already present in the garden soil, it is however, sheer poison if used alone in a pot. Not only does the water added to the pot saturate the root space and displace life giving oxygen, but the table scrap compost starts to ferment without oxygen. This anaerobic fermentation of the compost produces toxic compounds and gasses that hasten the death of the already oxygen starved roots. Having a hole in pot filled with this vile mix does little to improve the conditions as a physical force called the “capillary force” that is powered by waters’ attraction to small, cylindrical linear spaces keeps the water the soil like the two components of Velcro keep each other well attached.
So, as I suggested, you need to either replant the citrus in a pot with ½ cactus mix and ½ “potting soil “ (make sure the bag specifies the word ‘potting’) or replant a new one in the same. I would start with a new plant, as the weakened condition of the tree has made it labile to disease and has increased the possibility that if you transplant it, your will also transplant a large quantity of disease producing fungal spores (like Phytophthora, see video of spores) as well.