How to Use Worm Castings

Worm castings (vermicompost,worm poop, worm manure) can be used in many different ways and with any type of plant to provide essential nutrients and beneficial bacteria. Can be stored indefinitely in a cool dark place. Always store with air holes. Here are some common ways people use worm castings:

1) Top Dressing- sprinkling worm castings near the base of the plant will gradually allow the nutrients and bacteria to penetrate the soil and travel to the plant roots every time you water your plant.

2) Mixing into Soil- can be done before planting or carefully near the plant roots and will allow the plant roots to access the casting nutrients and beneficial bacteria faster than top dressing. If planting in a pot, mix into the soil 10% to 25% worm castings by volume. If in the ground, mix into the soil roughly 1 liter per 1 square foot of ground.

3) Using with Other Amendments- worm castings work well with other amendments such as manure composts or powdered amendments. For example, use worm castings together with composted manure to get the beneficial bacteria of worm castings but the affordability of composted manure. 

4) Make your own Potting Mixes- worm castings can be used with any neutral medium or potting mix with good results. For example, you can reuse and rejuvenate old potting soil by adding worm castings. Or you can mix worm castings with mediums such as compost, coco coir, composted mulch, peat moss, bark fines and other amendments to make your own soil mixes.

5) Use as a Seed Starter- add worm castings to your seed starter mix to increase germination rates and decrease germination times. The beneficial bacteria and moisture retention properties will help you start your seeds as soon as possible and get healthy seedlings.

6) Grow Large Plants and Encourage Root Growth- plants grown with worm castings will grow to their full potential and their root structure will be large. Potted plants grown with worm castings get root bound easily due to high root growth and will require larger pots quickly!

How to Use Worm Tea

Worm tea (worm casting tea, worm compost tea, vermicompost tea) can be used on any plant and provides fast nutrition and beneficial bacteria to the plant roots and soil. Can be stored indefinitely in a cool dark place for 6 months. Common uses for worm tea are as follows:

1) Provide Fast Nutrition to Plants- pour worm tea plus water at the base of the plant and see results in as little as 24 hours. Because the worm tea is worm casting extract, the nutrition is already dissolved and instantly available if absorbed by the plant roots. Worm tea can be diluted 10 parts water to 1 part worm tea for healthy plants or 1 part water to 1 part worm tea if faster results are desired. Use on a regular basis for best results.

2) Rescue a Struggling Plant- pour 1/4 - 1/2 cup of straight worm tea at the base of the struggling plant every 24 hours. If the plant is small or young, the worm tea can be diluted 1 part water to 1 part worm tea. Repeat until plant shows recovery. This is especially helpful when there is not enough time in the season to start a new plant.

3) Use Instead of Repotting Plant- worm tea can extend the time a plant can remain in its current pot. You may not be able to repot a plant that needs it immediately for various reasons including time, access, convenience, or supplies available. Perhaps you have a plant that is close to the end of its life but needs to be repotted. Instead, you can feed it worm tea to keep it healthy until it is time to start over with a new plant. Another example would be to feed worm tea to seedlings that cannot be planted yet due to time or weather.

How to Start a Worm Bin

DIY Indoor Worm Bin

The most popular way to start a worm bin is to make a do-it-yourself worm bin from plastic storage totes such as rubbermaid bins. The following is a step-by-step guide for an indoor plastic DIY worm bin:

1) Find 2 plastic storage bins that can nest in one another but 2 different heights. The deeper bin will be on the bottom to catch excess moisture and the shallower bin will nest in the deeper bin on top and house the worms, bedding, and food. A good example is to get a 37.9 liter and a 53 liter rubbermaid bin. The 37.9 liter rubbermaid bin, 24 x 16 x 8-3/4" (61 x 41 x 22.2 cm), is roughly the deepest that should be considered. Anything deeper will be extremely heavy to lift when full and too deep to allow good air flow to the full depth of the bedding.

2) Drill drainage holes in the shallower bin only. Drill roughly a dozen drainage holes evenly spaced throughout the bottom of the shallower bin. The drainage hole diameter can be 1/4". Food scraps can generate a large amount of excess moisture and therefore drainage is extremely important to avoid flooding your worm bin.

3) Nest the shallower bin inside the deeper bin.

4) Prepare the worm bedding. Good worm bedding is arguably the most important factor for success. The following materials can make good worm bedding: high quality potting mix, finished and aged compost, composted mulch, coco coir, cross-cut or micro shredded cardboard, ph balanced peat moss. One or a mixture of these materials will make your worms happy in their new environment. Prepare the bedding and saturate the bedding with water enough so a couple drops of water come out of the bedding when squeezed by hand. Fill the bottom half of the shallower bin with the moist bedding.

5) Release your worms into your bedding. Try to use at least 1/2 a pound of worms for a rubbermaid sized bin. Otherwise the bin may be too large for the worms to spread bacteria and break down food efficiently. Allow them to burrow and check on them every couple of hours to see if they like their bedding. If they are spread out evenly throughout the bedding, it means they are comfortable and like their bedding. If the worms are bunching together in balls or climbing the walls on mass, the bedding is likely far from neutral PH, 7.0, or is noxious to them such as high in toxic gases such as ammonia from unfinished compost. It will be apparent whether they like their bedding after 1 or 2 days of checking.

6) If your worms do not like their bedding, take them out and try a different bedding mix. If your worms like their bedding you can begin feeding them food scraps. Try and cut the food scraps into small pieces or even puree the food to start as the beneficial bacteria needed to soften the food has not built up yet. Feed on top of the bedding to maximize air flow. Cover the food scraps with a sheet of dark plastic or wet newspaper to keep the food scraps moist. Start with 1 cup of food and do not feed more until the food is completely eaten.

7) Keep your worm bin in a warm part of your home. The warmer the temperature, the faster the worms can turn food into castings and the faster they will multiply. above 20 degrees celsius is an optimum temperature. Temperature exceeding 35 degrees celsius can cook your worms however. The most common way of cooking your worms is heavy feeding and sealing the bin with a lid. We recommend not using the lid or drilling a dozen 1 inch holes in the lid to allow for maximum air flow.

Bin Maintenance:

  • Once a month lift the shallower bin and check the deeper bin for excess liquid. This liquid is called leachate and should be removed regularly. It can be diluted 100 parts water to 1 part leachate and used to water plants or it can simply be disposed of.
  • You can also feed by burying your food scraps in the bedding rather than top feed. This is personal preference. However, top feeding under a piece of dark plastic or moist newspaper is also a good option and food scraps soften and break down fastest on top of the bedding where there is maximum air flow.