In this feature, garden authority Gayla Trail, the creator of YouGrowGirl.com, answers frequently asked questions and offers gardening advice.
I recently purchased an 18″ tall potted Meyer lemon tree. It was loaded with buds and had four 3/4 inch lemons. I placed it in a screened porch that gets light most of the day. I fertilized it with an acid fertilizer and watered per instructions. Recently the lower leaves have yellowed and fallen off, the buds are falling off and the lemons are turning yellow. Can you please advise as to what to do to keep from losing this tree?
Thanks in advance.
Congratulations on your new tree! Meyer lemons are the very best in my opinion, but they can be a little bit fussy in pots. A range of conditions can lead to immediate and rather startling leaf drop. I find it can take some adjustment before you hit on the right formula that meets their needs and gets things back on track.
All citrus trees grown in pots thrive on a balance of three things: bright light, consistent moisture and good drainage. The first thing that came to mind when you described your plant was the shift in growing conditions that plants experience when moved from a garden center to their new home. Citrus trees tend to be extra sensitive to that shift and what seems like a minor change in light intensity or the amount of humidity or water it receives can cause leaves and developing fruit to drop almost overnight.
Sunlight: Lemon trees need eight hours of direct sun per day. You can get away with six, especially during the winter off-season, but bright light is required for good fruit production. If the light coming through your porch screen is filtered, it may not be enough. Is there any chance that you can put the tree outside for the rest of the summer? My citrus trees have always flourished with this treatment. Regardless of what I thought they were getting inside, nothing beat those months outdoors. If you go this route I suggest placing it in a protected spot with partial shade for a few weeks so that the tree can adjust, and gradually moving it out into direct light.
If the sunlight on your porch is truly as direct as the sun outside then you might want to consider the heat it receives. My south-facing porch is backed by a brick wall that absorbs heat during the day and releases it at night. Citrus trees love sunshine but they will drop their leaves if they get too hot, especially around the roots. For that reason black pots can be a poor choice, which is ironic since every fruit tree I have ever purchased came in one.
Watering: Water deeply, but infrequently. The soil should dry out slightly between waterings. Leaf drop can be caused by soggy soil and water that stagnates in the tray. So make sure to dump it out after a good, long soak. You’ll know it is time to water when the soil is dry a couple of inches down into the pot. Use your finger to check.
Soil: As I mentioned above, good drainage is absolutely key. A new plant straight from the garden shop should come potted up in an appropriate medium, but if you do decide to repot choose soil that is very well draining, yet nutrient-rich and slightly acidic.
To make your own mix: Add one part orchid bark to three parts potting soil. Try not to upgrade to a much larger pot immediately. Citrus trees have shallow, but far reaching roots and prefer being moved into slightly wider containers that aren’t significantly deeper than their current pot.