@Daisy78 Typically, necrotic leaf tips and margins are indicative of an unhappy root system unable to function normally and keep the plant's most distal parts fully hydrated. The most common causes are over-watering, a high level of dissolved solids (salts) in the soil solution, or under-watering. Over-watering is undoubtedly the most common cause, with second place going to either under-watering or a high level of dissolved solids. All three issues limit the root's ability to do their job.
If you are watering when you can still detect moisture in the top 2-4" of the soil, you're almost certainly over-watering. If the plant has wilted due to lack of water, you could obviously be over-watering. If there is no drain hole in the pot, it
significantly increases the probability you're over-watering; and, since lack of a drain hole makes it impossible to flush accumulating salts from fertilizer solutions and tapwater from the soil. As the level of dissolved solids increases, it makes it increasingly difficult for the plant to take up water and the nutrients dissolves therein.
The key questions are:
* Does the pot have a drain hole?
* How are you determining when it's time to water?
* If the pot does have a drain hole, are you watering in dribs/drabs to prevent over-watering, or are you watering so the entire soil column is saturated and at least 20% of the water applied exits the drain hole; thereby carrying accumulating salts out of the soil in the excess water?
Too, if you are using a fertilizer that derives it's nitrogen from organic or ammoniacal sources, or urea, you might very well be looking at ammonium toxicity. This would be especially true if A) the soil temp is below 55*F, B) you are over-watering, or C) soil compaction or root congestion is limiting the root's oxygen supply.
Al
Al