Zeus and Kepler needed watering today. I suspect that there may be salt build up in the soil. When I water them from the top with fertilizer, I leave them in a bowl where excess liquid pools up at the bottom. I think that this keeps salt levels high at the bottom of the pot. This time, I used regular water and placed the pots on a rack above the bowl, allowing the excess water to drain out, hopefully removing excess salt completely. I did one elephants worth (our watering can) for each, which is about 56 oz which allowed a fair amount of water to drain out. It’s possible that the excess salt was stressing the plants, causing the aerial roots to form.
The other possibility, maybe more likely, is that the high chlorine content of the water is stressing the plants (more on this below). I should consider leaving water out overnight for the chlorine to evaporate, but I’m constrained to about 100 oz, and also by space. I don’t want Taco sticking his face in there (as it may have chemicals from the fertilizer in it). I’ll have to think more about a solution for that.
I came across this great resource: http://www.growell.co.uk/blog/2011/04/talking-to-your-plants-part-1-body-language
Some particularly interesting points:
Best place to look is new shoot growth. This will tell you if previous problems have been overcome.
Problems starting at the base of the plant
A shortage of main nutritional elements first appear near the base of the plant (they tend to flow freely to the top of the plant, where they are required). Nitrogen, phosphorous, potassium.
- Yellowing of larger leaves from the tips and margins inwards: potassium
- Yellowing of the tips spreading evenly back towards the stem of larger lower leaves: nitrogen
- Dark purple tinge to larger green leaves and purpling of the stems: phosphorous deficiency
- Iron deficiency: interveinal color loss.
- Calcium deficiency: necrosis of young leaves at the growing tips, looking brown and crispy, but early signs can also show as brown necrotic spots in the middle to older leaves.
- Cold nights
- Bleaching from light being too close
- Initially leads to subtle loss of surface sheen followed by yellowing and rust spots a couple of weeks after the initial damage was done.
- These leaves slowly start to die as the stomata fail to function properly.
- 18 hours of intense light is very demanding on young plants, but bigger plants can deal with it better.
- To keep cool, plant over transpires. May immediately suffer from blotchy marks and loss of shine, additional thickness, and a smooth green look for a few days. Then you start to see loss of color all over, especially between the leaf veins where rusty spots often appear. The latter become visible a couple weeks after the damage has been done, a few inches under the fresh shoots.
- Room too hot, light too close at some stage.
- Frequently mistaken for nutrient difficiency, which is actually quite rare.
- wind burn
- overly warm nutrient solutions
- limiting oxygen at the root level that’s required for nutrient uptake.
- Makes plant look droopy, grow very slowly, and deventually develop colour loss and deficiencies.
- Magnesium defficiency: show on middle to older leaves starting off by turning yellow, but the leaf veins stay green (interveinal chlorosis). As deficiency progresses, brown rusty spots / burnt patches on leaves will occur. This is easily corrected by a foliar spray of CalMag.
The light bleaching description sounds an awful lot like what happened to a few of Zeus and Kepler’s leaves early on. I just need to go easier on the light, and I think I have.
Color loss on old large leaves
Very normal. Often lose color due to lack of light and then fall off. Leaves will be replaced by new growth nearer the light source.
Yellowing of leaf tips
Common and hard to avoid. With no other symptoms, probably mild form of wind burn.
- Phosphorus deficiency (also check for purpling of the leaves).
- Cold conditions
- Normal plant genetics
- Natural for latter part of 18 hour light cycle.
Larger bottom leaf loss is not unusual for fast-growing, light-loving plants. Light competition, and key nutrients are directed up and out to new growth.
Upward leaf tip curl
- leaf is trying to retain moisture. – light positioned too close.
- Wind burn
- Lights too close
- not enough air exchange
- typically environmental rather than nutrient
Curling down of leaf margin
- Problems in root zone
- inappropriate temperatures
- unsatisfactory levels of oxygen
Curling up margins
- Same environmental issues that trigger leaf tip curl up.
Leaves too small
- overfeeding the plant
curl or hook downwards at the tip
Leaf color too dark or dull
Leaves a little too narrow, lacking in colour, and under sized/misshapen
- Deficiency of a main element – increase feed strength slightly.
Twisting and mutating of new leaves
- Unstable genetics
- Lack of calcium, silicon
- More common: excess chlorine (de-chlorinate tap water in a bucket for at least 12 hours before use)
Looks like the mutating leaves on Zeus might be due to high chlorine content in the tap water. I’ll try to make sure that I have water around for at least 12 hours before I water Zeus and Kepler.