My neighbor's old coffee grounds trick backfired on my ferns

I read online that used coffee grounds are great for acid loving plants, so I started saving mine from my morning pot. I had this big Boston fern that was looking a bit sad, so I mixed a full cup of grounds right into the top soil, thinking I was giving it a treat. About four days later, the fronds started turning yellow and crispy at the tips. I panicked and dug a little, and the soil was packed down and smelled kind of sour. Turns out I used way too much and it basically formed a crust that blocked water and air. I had to repot the whole thing with fresh mix to save it. Learned that a light sprinkle, maybe a tablespoon mixed in, is the max for something like that. Has anyone else had a plant react badly to a 'free fertilizer' tip?

2 comments

2 Comments

grantthomas15h ago

Coffee grounds are tricky. They pack down into a dense, wet mat that just suffocates the roots. A full cup is way too much for a potted plant. I've had the same thing happen with leftover tea leaves. The best method is to mix a tiny amount into your compost pile first, then use that compost later. Straight from the pot to the plant is a gamble.

jessicaw1114h ago

Wait a full cup? @grantthomas that's wild, no wonder the plant died. I only ever sprinkle like a spoonful on top of the soil.