Cure the Vermicompost Harvest Problem

Growing worms is easy.

Get a box, toss in paper and food, enjoy the worms. There’s a bit more to it but it’s not rocket science or brain surgery. That is, until you want to harvest the Black Gold vermicompost. After a couple of months of mixing cardboard, carrot tops, eggshells, napkins, coffee grounds, and leftovers, you have good worm farm going. But you don’t want to put all those scraps into your soil. How do you harvest the good stuff if it’s buried in shredded paper and food scraps?

This plan is aimed at worm people with a typical box style worm farm. A lot of people use that black box with a yellow lid, easy-peasy. Any box will do the same. The other major style of worm bin is stacking trays. Those have different issues and benefits. For now, let’s stick with the simple box of worms.

Harvesting is hard.

In eight weeks, your full worm bin looks good. The plump worms are eating and making babies. There is fertile looking black ‘soil’ in the box. But the good worm poop is mixed with unfinished chunks. How do you get just that good stuff? Most harvest answers involve sifting or sorting to get the fine-grained good castings away from the chunky stuff. I hate sifting. Sifting takes a lot of time, and the darn screen clogs up. Sorting isn’t any better. You poke at the mix, pulling out big clods, but you know there are a lot of lumps that you just can’t bother with. The half-finished box is hard to harvest.

Cure the problem.

I instead use time to solve this problem. This is called ‘Curing’.

Curing is time for the worms to work with no fresh food or bedding for a month or two until they finish the job completely. The good-looking bin of chunky vermicompost turns into great looking smooth vermicasts, perfect for your garden. I like to play with my worm bin while it cures. I toss the contents like a fancy salad. It gives me a chance to check worm health and bed moisture. While I’m tossing, I bust up the lumps of paper bedding for smooth casts. I mix the too moist bottom into the slightly dry top. I turn the slow corners in to finish in the middle of the pile. The bed looks better with every toss.

While the first bin is finishing, keep the farm going in a second bin. Starting the second bin is much easier because you now know what you are doing. You make a fresh bin of bedding, add some of your worms and keep growing. In two months, it will be ready to cure and now you have two bins. One is to feed and grow; the other is curing.

Harvest the casts.

Cured vermicasts are far easier to harvest. It is now a mix of fine-grained casts with worms and the worms will do most of the harvest work for you. Open the bin, remove the worm blanket, and give it one last good toss. The worms see the light and run away; they dive down for safety. After ten or fifteen minutes, you scrape off the top inch or so. This is your worm free harvest. Wait another ten minutes and repeat. The worms will keep diving until they bunch up at the bottom of the bin. Add fresh bedding to the concentrated worms and your bin is restarted.

Cycle for happiness.

Cycling between feeding and curing makes the worms happy, and you get a nice pile of clean vermicasts every two months. Fresh, moist, homegrown vermicasts are better than the store-bought dust just like homegrown tomatoes are better than any grocery store ‘tomato’. Now, your harvest problem is cured.