With warmer weather coming, people who compost with worms are anticipating the planting season! Gardeners are making lists and garden layouts on graph paper or computers. Lawn owners are contemplating whether to sow more seed and when to fertilize. Meanwhile, the composting worms are munching away, making compost from kitchen scraps. It’s nearly time for spring cleaning at the vermicomposting bin!
The composter’s location has an impact on harvesting. The composter is either indoors or outdoors.
In cold winter climates, outdoor composters have been mostly dormant for the winter. It’s possible that most, or all, of the composting worms died. They likely left eggs behind, which will hatch when the weather warms up. Meanwhile, the kitchen scraps have been piling up at the top of the bin.
Mother Nature will start naturally breaking down the material faster when the weather warms up. You can wait for the worms to hatch, or order more composting worms from Uncle Jim’s Worm Farm. When you need to harvest finished compost, you will find it at the bottom of the bin. Skip ahead to “Harvest the Finished Compost.”
Coddled in a warmer environment, worms in an indoor composter are active and busy eating. The valuable worm castings are accumulating. These castings are the perfect organic fertilizer that gardeners seek.
If you are using a tray-based composter, you might have quite a few trays piled up. So long as you are feeding only in the top tray, the lower trays will have few worms. Harvesting the finished compost is easy. Examples of tray-based composters are the Worm Factory 360 and the Worm Café.
Harvest the Finished Compost
The finished compost is dark in color. In a tray-based composter, it’s most concentrated in the lower trays (so long as you have been feeding only in the top tray). In a regular, active composting bin, the worms have digested most of the scraps and original bedding. The worms are living in the finished compost. And in an outdoor bin that sat through a cold winter, the uncomposted scraps are on the top — therefore, the finished compost is on the bottom. If your outdoor bin has a pull-out tray or door near the bottom, you will have easy access to the compost.
You will need to separate the finished compost from the other items in the worm bin, which are:
- Composting worms
- Undigestested scraps
- Trash, such as stickers from produce
- Pits that won’t break down
- Anything that has sprouted
Owners of tray-based systems are pretty much done. Just take pull out the lowest tray and inspect it for worms and trash. A couple of stray worms won’t harm your gardening. Remove any unwanted items. If there is a lot of unwanted material, or if the compost seems too compact, you can “screen” it. See instructions on building a screen for compost harvesting.
There are several techniques for harvesting compost.
- Manual separation: In a deep bin, “turn” the compost using a pitchfork or shovel. Full instructions are on our blog post, “How to Harvest Your Compost.”
- Screening: Suitable for shallow bins, as well as compost from deep bins that need more processing. It’s easy to buy or make a simple screen. Instructions are in this short video about making a composting screen. Shake the compost through the screen. Finished compost filters through, while worms, sticks, debris, etc. are caught by the screen.
- Piles: Dump the bin onto a tarp. Divide the worm bedding into cone-shaped piles. The worms won’t like the light, so they will dig down. Wait 20 minutes, then brush off the piles. Repeat the brushing until you have the compost you need. Then, put the worms and the remaining bedding back in the bin.
- Hand-Harvest: Tediously pick through the bedding. Immediately put worms back into the bin so they do not dry out. This is useful if you need a small amount or don’t care if worms are in your finished compost. Screening is faster and more efficient.
How to Use Finished Compost
You can use the finished compost immediately. Or, set it aside in a bucket or sack. Valuable microorganisms from the worms’ digestive tracts are living in the worm castings. Fresh is best, but the compost is still useful for a long time.
Evaluate Your Worm Bin
Take a look at the worm bin. Is it still serving your needs? Are there far more worms than your composter can handle? The worm population will itself balance out — but a bumper crop implies you have enough scraps to produce more compost. If the bin is too small, consider getting a bigger one or starting an additional composter. Have your worms have died out? Wait to see if their population recovers, or order more composting worms from Uncle Jim’s Worm Farm.
Composting worms are reliable workers. So long as the conditions are right and the food is plentiful, worms will turn trash into treasure. Gardeners everywhere swear by vermicomposting to get the best organic fertilizer. Take care of your worms, and they will take care of you!
Note: If you want to bypass composting and just purchase finished compost, order finished online from Uncle Jim’s Worm Farm. Our worms make it at our worm farm in rural Pennsylvania.