Sunday, 25 October 2020

Coco Coir Litres to Cubic Metres

Q: What is the volume of 1 Litre of water?

A: A litre is a cubic decimetre, which is the volume of a cube 10 centimetres × 10 centimetres × 10 centimetres (1 L ≡ 1 dm3 ≡ 1000 cm3). Hence 1 L ≡ 0.001 m3 ≡ 1000 cm3, and 1 m3 (i.e. a cubic metre, which is the SI unit for volume) is exactly 1000 L.

The Coco Grow Pure Coir Compost is sold as a 5kg block with dimensions of 30cm x 30cm x 11cm and weight of 5kg and the website states that:

How To Use It:
Simply put your compressed Coco Coir Peat brick in a container, add water and let it sit until the water is absorbed (approx. 20min). Fluff it up and you are ready to use it. After adding water the 5kg block expands in to 75ltr of compost.

Key Benefits:

- 100% peat-free
- pH and nutrient balanced
- Sustainable and environmentally friendly, from natural renewable sources, biodegradable
- Easy to handle, uniform in composition, odourless
- Better water retention, long lasting
- Provides good drainage / good aeration
- Free of bacteria and weed seeds
- Absorbs water readily and re-wets easily, reducing the need for wetting agents
- Can be reused repeatedly

I will be covering what the difference is between the different varieties of Coco Coir in the photo at the top of this article in a later posting, and which ones I intend to use and why.   

Weight 5kg, size: 30 x 11 x 30cm when compressed, expands in to 75 litres of Peat Free Coco Coir Compost - pH value 5.5 -6.8

But what I really want to know

Looking at my square foot gardening beds which are 1.22x x 1.22m (4ft x 4ft) internally on plan and working to a depth of 150mm or 0.15m (6 inches) the required cubic metres of Mels Mix required is 1.22 x 1.22 x 0.15m = 0.223 m3 required per bed.

So Dividing the volume 75 litres by a 1000 gives the answer that one hydrated block will fill a volume of 0.075 m3

If using the metric equivalent and using squares that are 300x300 and beds that are 1.2m x 1.2m internally then the volume for 150mm thick is 1.2m x 1.2m x 0.15m = 0.216 m3 and a third of that for "Mels mix" would be 0.216m3 / 3 = 0.072 m3 of Coco Coir required per bed. 

So how many cubic metres does 75 litres of coir provide?

If 1m3  = 1000 Litres then 75 litres of coir is equivalent to 75 / 1000 = 0.075 m3 

“Mel’s Mix” was created by Mel Bartholomew, after much experimentation. Mel concluded that his formulation of 1/3 peat moss or coconut coir, 1/3 vermiculite and 1/3 blended compost yielded superior results in only a 6 inches (15 cm) depth. 

The benefits of the mix included keeping soil friable and virtually weed free with all the necessary nutrients. This mix eliminated the need for artificial fertilizer as compost is added each time you re-plant a square which provides enough nutrients naturally.

0.223 m3 required in total thus

0.233 m3 / 3 = 0.074 m3 thus the block is nearly exactly the right amount for a third of the mix required when re-hydrated for one bed. I wondered if this was pure coincidence or was it done by design. I asked cocoandcoir and it's just a happy coincidence they wanted something that would give the same volume as compost.    

Now having established the amount of litres required per bed I also know how much vermiculite and blended compost that I'm going to require to fill them. 

More on Coir and Vermiculite to follow......   

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