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All Things Organic Blog

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How Castings Help Drought

June 10th, 2016 | by Mel-Lynda Andersen | in Worms |    0   

This is a blog that was published on our previous website back in 2014, and is being reposted because it's coming up to drought season when castings come in handy! 

I know I’m not alone when I say thank GOODNESS we got some summer rains recently!

On that note, if you are like us, your lawn, shrubs, bedding plants and vegetable gardens have been moisture-challenged these past weeks. If they weren’t you were probably regularly watering to keep them moistened.

How can we help our plants be prepared for surviving drought, and minimize our water use? (Smart glasses camel)

Improved water retention is accomplished in a lot of different ways. For example, in the sandy, well-drained soils of our community Brookswood in Langley, B.C., we worked castings into the top layer of soil in our gardens. (Soil layer diagram)

Castings are made up of much smaller-sized particles when compared to the predominant coarse and fine sands that make up our soils. These fine particles provide more places for the moisture to attach than do the coarser particles. Castings diversify soil particle size and improve soil structure; they enhance moisture penetration and increase water retention in the soil over drought stricken periods. Humic acid, found to encapsulate each individual casting, helps hold onto moisture. Overall, plants are able to access precious moisture more readily, and for longer periods of time when worm casting are used to amend soil. (golem)

Castings not only help reduce drought and improve moisture retention with humic acid, they also contribute key minerals and nutrients to the soil. These include potash, nitrogen, potassium, magnesium and calcium. Higher soil micro-bacteria levels found in castings (and even more so in castings tea) increase micro-biotic activity in garden soils, facilitating plant nutrient uptake. The plants are the obvious beneficiaries of this enhanced process and these nutrients. 

Longer access to moisture, increased micro-bacterial activity, and the readily available minerals and nutrients contained in castings, all contribute to improved plant health. Healthy plants are better prepared to survive drought conditions than less vigorous specimens. (be prepared)

On the hole (pun intended) regularly adding worm castings to soils, particularly to well-drained coastal BC soils, enhances soil moisture penetration and retention,  improves micro-bacterial activity, and the castings provides the soil and plants important minerals and nutrients. Plants get healthy, and stay healthy, longer, even during drought. (happy sunflower)

Help your plants look good, and make it through the long dry summer. (Because it’s looking to be that way this year!) Judiciously water…. and incorporate plenty of worm castings in your gardens! Oh yes, and cross your fingers and hope for rain!



  1. Kids for Landcare: Wormwatch, Education Department of South Australia, 1992, p. 35.

“Castings contain: 5 times the available nitrogen, 7 times the available potash and 1 1/2 times more calcium than that found in 15 cm of good top soil. Therefore, castings are supplied with available nutrients. The nutrients are also water soluble and immediately available to plant life. You will find that most potting soils have nutrient life of 2-5 days, where worm castings will last up to 6 times as long as other types of potting soils. You will need 5 times as much potting soil to do the same job as the worm castings. So, in the long run, worm castings are much cheaper and do a much better job. Also, castings hold 2-3 times their weight in water. That means you water less and the pot will stay damper for a longer period. Worm castings will not burn your plants; unlike using any fresh raw manure (cow, horse, etc.) which can burn root systems if it is not applied properly. The advantage of using castings is the manure passes through the worms' digestive system producing rich organic plant food and a slow releasing fertilizer that allows for better growth.”

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  1. Volume I “Scientific Earthworm Farming.” 1975, p.175

“Earthworm castings are the best imaginable potting soil for greenhouses or houseplants, as well as gardening and farming. It will not burn even the most delicate plants and all nutrients are water-soluble, making it an immediate plant food. Earthworm castings, in addition to their use as potting soil, can be used as a planting soil for trees, vegetables, shrubs, and flowers. They may be used as mulch so that the minerals leach directly into the ground when watered. The effects of earthworm castings used in any of these ways are immediately visible. The make plants grow fast and strong. Nematodes and diseases will not ruin gardens or plants if the soil is rich enough for them to grow fast. It is the weak plant in poor soil that is destroyed by nematodes and diseases.”

R.E. Gaddie and D.E. Douglas, Earthworms for Ecology and Profit

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