Basil leaves going white - why?

Question

A couple of weeks ago my basil plant on the window started to have some leaves withering and going black.

Initially, I thought that it was due to over-watering it and lowered the watering volume, but that didn't solve the problem.

Why could they have been turning white and withering like this? Especially only on some branches, but not all?

The picture above is one of the whiting leaves on the branch with four normal ones. — chiffa, Jul 26 '18 at 16:11
How long have you had this plant, and has it always been in the same pot? — Bamboo, Jul 26 '18 at 17:16
@Bamboo: about 3 months now and yes, it has always been in the same pot. — chiffa, Jul 26 '18 at 18:29
The small leaves just above the top of the pot that I can just about see - are they basil, or some other plant? — Bamboo, Jul 26 '18 at 18:45

score 1 · Answer 1 · answered Jul 26 '18 at 19:15

I hope I've got this right - you seem to be saying your Basil is growing in the same pot as Rosemary, Sage and Thyme, and that its been in the same pot for three months. If I have got that right, its not really surprising that your Basil is having trouble thriving. Basil is an annual plant; Rosemary is a large, evergreen shrub that wants to get 6 x 6 feet, Sage is another shrub that makes about a foot tall and twice as wide, French Thyme is a slow growing sub-shrub. All take up root space, and are, by now, depriving your Basil of its root room.

All these should be growing in separate pots, but in regard to your Basil, that too deserves its own pot, though the season is getting on a bit now to try splitting and repotting them all from the Basil point of view, given its only an annual. I think I can see young Basil leaves growing lower down, so maybe just cut back the woodier stems and hope that the Basil doesn't lose the unequal struggle to survive in the same container as all the other plants.

Thanks for the advice! I will definitely plant them differently next year! — chiffa, Jul 26 '18 at 19:32

score 1 · Answer 2 · answered Jul 28 '18 at 10:12

The reason your older leaves are going white, actually yellow, is that the plant is experiencing nitrogen deficiency. Nitrogen is a mobile nutrient, and when new leaves grow in a state of nitrogen deficiency they take nitrogen from the old leaves which turns them chlorotic.

The deficiency is caused by the over crowding in your container. You need to add some npk or grow the plants in their separate containers.

Basil leaves going white - why?

2 Answers2