I’ve always been curious about why most succulent fertilisers contain low levels of nitrogen. Nitrogen’s responsible for leaf and plant growth so surely the more it gets the bigger and better it’ll grow right?
Well…not exactly. Before we get into it, I’m not an expert and despite scouring the darkest depths of the internet to find out why succulents respond better to low nitrogen fertilisers there wasn’t one clear answer. Here’s what I could figure out from my sleuthing:
When succulents get too much nitrogen (N) it can stop the plant from being able to take up potassium (K). Potassium is responsible for overall plant health, it helps move nutrients and water through the plant as well as increasing disease resistance and promoting overall growth of both the roots and the plant.
If your succulent can’t absorb potassium then it’s growth will be stunted and you might start seeing the oldest leaves on the plant start to curl at the edges along with brown burnt looking tips.
Etiolation (Leggy Growth)
Leggy growth is caused by the plant not getting enough light so it starts to stretch out. Once your succulent gets leggy growth there’s no way to reverse and the only real solution is to snip it off.
Even though etiolation is usually caused by a lack of light, too much nitrogen can make the problem worse by encouraging the plant to push out lots of new growth too fast. Even if your plant is getting plenty of sun a sudden dose of nitrogen can still disrupt its natural growth pattern and cause leggy growth.
Recognising Nitrogen Deficiency
One of the best thing about plants is they’ll let you know if they’re lacking in something. When it comes to nitrogen deficiency look out for the older leaves turning pale green or taking on a yellowish tinge. The colour change signifies that the plant is struggling to make enough chlorophyll which it needs for photosynthesis.
Another symptom of nitrogen deficiency is reduced growth. Succulents tend to be fairly slow growing so it can be hard to tell if it’s regular growth for that particular succulent, whether it’s down to less than ideal conditions or if it’s gone dormant or semi dormant.
Seeing as most succulents can survive fairly happily for long periods of time without being fertilised at all it’s better to under fertilise than over fertilise. It might seem like nitrogen is going to make your plant grow faster but too much of it can have the opposite effect and end up harming your plant.