We have a 4 year old dwarf lemon tree. It has never flowered until this year. Many flowers and a lot of fruit, however the fruit seems to have stopped growing and has been stagnant for 3 weeks. We have 100 degree heat and this tree sees the morning sun. It is well watered. What can we do to get this fruit to start growing again?
The major factors of citrus tree success are:
Citrus are tropical plants which needs plenty of sunlight. Some are also shade tolerant. So place it near a window which is facing north or south(according to the place you live) so that it can get maximum sunlight. More sunlight = More fruits.
- Soil acidity
It needs a soil pH in the range 6.0 to 7.0 for best results. So if your soil pH is very high(alkaline), you can bring it to the preffered range by adding Elemental Sulphur, which is most commonly used by organic gardeners. However, sulfur requires some time before it is converted to sulfuric acid with the aid of soil bacteria, to be plant available.
This is the thing where most people get it wrong. Citrus needs a well drained soil(https://goo.gl/NKljxG) with infrequent watering, means over watering can cause root rot and kill the plant. So as a rule of thump water only when the top soil gets dry to 1-2inch.
As a promoter of organic farming I'll suggest that using compost/vermicompost with other green manures will do just fine.
Remove some of the fruit.
Producing fruit is very strenuous for the tree. Once I had a small orange tree. It fruited and then died.
To take the burden off the tree you should limit the number of fruit it produces, especially if it is a young tree. As the tree matures, allow it to produce more and more.