Pilea lower leaves yellowing
Plant: Pilea peperomioides
How long have you had the plant? 1 to 6 months
Concerns:
I think the leaves started to yellow maybe 3-4 weeks ago. I thought I overwatered it so cut down the frequency of watering (used to be once per week) but I noticed that if I stopped watering for too long the leaves at the bottom will be droopy, a sign of lacking water.
As the situation seems to get worse it occurred to me that it might be a lighting problem, since the plant never had issue during the summer and recently there’s a building blocking my direct sun so I just added a grow light, not sure how long it takes to see results. Now my concern is just that could there be root rot as well and how should I water going forward?
Will definitely keep the grow light there and hopefully that could be replace sunlight. Should I also cut off the yellowed leaves to help plant recover or will they turn green again? Thanks so much!
How do you determine WHEN to water: I follow the schedule I was told/researched for this plant – I used to just water the plant every week with about 2 cups of water. My pot doesn’t have a drainage hole so now after I water I use the moist meter to see the condition of the soil and water whatever amounts till the meter says moist/wet.
Describe HOW you water: I pour a small amount of water onto the soil
What fertilizer do you use? I have never used fertilizer.
Darryl’s Analysis
Environment:
This is a great window – will produce good growth for the Pilea.
Effort:
Pouring a small amount of water will leave dry pockets where roots can die off – it’s better to evenly and fully moisten all parts of the soil and let the excess water drain away. But without drainage holes, the amount of water that will saturate a given volume of soil is roughly one quarter – so you should pour enough water to fill up roughly a quarter of the total volume of soil. Pour slowly and as evenly around the soil as possible. This is the HOW to water.
As for the WHEN to water, do it when the soil is about halfway dry (the exact time frame is irrelevant as long as you are observing the soil). Moisture meters aren’t more precise than a chopstick or simply lifting the pot – I’ve never needed to use one.
Because your light has been so strong, your plant has been using up soil nutrients quickly. The fact that you’ve never used fertilizer is the reason for the alarming rate of yellowing leaves. Rapid growth = rapid nutrient uptake; you should use fertilizer at every watering at the recommended dosage – here are some that I recommend.
I don’t think the grow light is necessary with such a large window but if you want to use it, it won’t hurt. But just for your calibration on light levels: a small grow light at that distance is roughly 400-600 FC but quickly falling to around 100 FC within a foot away. The sun shining directly on the plant through a window will be 4000-6000 FC – 10x more which means (in very rough sense), your grow light would need to be on for 10 hours to match 1 hour of direct sun (and again, this is only for the top of the plant).
Expectations:
Unfortunately, once yellowing begins on lower leaves (meaning, the oldest leaves), there’s no way to reverse it. But losing older leaves is inevitable even if you had been using fertilizer all this time – they would have simply fallen off later.
The most critical thing you should embrace is this: leaves have a limited lifespan. That means they will die at some point regardless of how “good” your conditions/care are. The goal is to ensure you have the best possible conditions and care efforts so the plant keeps putting up NEW growth.
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