"Rust" on leaves...
- Thread starter haoleflip
- Start date
dl290485
Well-Known Member
1- Is it only happening on the lower leaves? If it is, and being mid flower, you could suspect K deficiency. You can rule it out though if it is occurring on the youngest leaves before the older ones, as K is mobile and can/will be taken from the oldest growth to support the youngest. Potasium deficiency can cause heat problems within the leaf, and that's why it can look like a burn (because it is).
2- What are you temperatures like? This could be a heat burn. Do you monitor the environment? If it hasn't been over 35 Celsius then that's probably not it unless the humidity is really high too maybe.
3- I think it's at least possible it's a fertilizer salt build up (which blocks the leaves and causes a heat build up which burns) but it would be likely that if that were the case that the young leaves at the top cop it worse. The first sign of too much salt is usually the youngest leaves with browning tips and starting to curl. The salt travels right to the 'end of the line' following the water pressure but doesn't transpire away with the water nor is it used so it lodges in the end of leaves (and backs up from there). So basically what i'm saying is check your young smaller leaves up the top and if they look fine, it's not likely to be salt in my opinion.
2- What are you temperatures like? This could be a heat burn. Do you monitor the environment? If it hasn't been over 35 Celsius then that's probably not it unless the humidity is really high too maybe.
3- I think it's at least possible it's a fertilizer salt build up (which blocks the leaves and causes a heat build up which burns) but it would be likely that if that were the case that the young leaves at the top cop it worse. The first sign of too much salt is usually the youngest leaves with browning tips and starting to curl. The salt travels right to the 'end of the line' following the water pressure but doesn't transpire away with the water nor is it used so it lodges in the end of leaves (and backs up from there). So basically what i'm saying is check your young smaller leaves up the top and if they look fine, it's not likely to be salt in my opinion.
dl290485
Well-Known Member
Hmm ok. Do you mean bottled organic or using compost teas, top dressing and etc? Also if it's from a bottle, check if it's full organic or just 'organic based'. But yeah even from a bottled organic product you wouldn't get salt build up like chem fertilizer (if at all?). So maybe not that.
But what about question 1, is it only on the lower leaves? If it progresses from the older leaves at the bottom and works its way up over time it could be K maybe- but the rusting spots from that usually come coupled with some yellowing.
If you look at the first photo, not at the leaves in the foreground but behind them (up the top and a little to the left in the photo) you can see a lower leaf that has yellowing and the rusting like what I expect a K deficiency to look like- but the leaves in the foreground only have the rust... so yeah still a suspect anyway I think.
But what about question 1, is it only on the lower leaves? If it progresses from the older leaves at the bottom and works its way up over time it could be K maybe- but the rusting spots from that usually come coupled with some yellowing.
If you look at the first photo, not at the leaves in the foreground but behind them (up the top and a little to the left in the photo) you can see a lower leaf that has yellowing and the rusting like what I expect a K deficiency to look like- but the leaves in the foreground only have the rust... so yeah still a suspect anyway I think.