As someone without a yard and only one houseplant (Oliver decided the others were litter boxes), one of my major issues with vermicomposting is what to do with the finished compost. I’ve actually given a bunch of it to my family in Maine before. But now that warmer weather’s here my porch is an ideal space for potted plants, so I can put the worms’ hard work to use. Worm castings are a great fertilizer—better than regular compost. How can I use it in houseplants?

• Mix compost directly in with potting soil or sand. The ideal ratio is 1:5. Don’t use much more compost than this or the soil will retain too much water and the plants’ roots will rot. This is exactly what happened the first time I tried this a couple years ago.
• Steep the compost in water and use the resulting “tea” as liquid fertilizer. Mix two tablespoons of compost per liter of water and let it stand for a day.
• Put a layer of compost on top of the soil. Same idea as the previous one, but it’s less work. It also retains moisture like mulch, but might actually encourage weeds.

Basil, dill, and chives

For the herbs that we planted, we mixed compost directly in with the potting soil. I don’t know if it’s the compost or all the rain we’ve been getting lately, but they’re going nuts. It’s hard to use them as fast as they grow. Unfortunately, some sort of sprouts that were seeds in the compost are popping up, too. I actually have to weed my potted plants!