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Author Topic: coco in seedling substrate  (Read 975 times)

Véronique Macrelle

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coco in seedling substrate
« on: December 19, 2022, 09:09:28 AM »
to perfect the drainage of my most delicate seedlings, i wanted to try adding coco fibre to my substrate.
 I bought a dehydrated block of coco for terrarium, in a garden center. (quite expensive)

but I was told that it could contain too much salt for the plants.  :-[

 does anyone use it and how, please?
what kind of coco should I use for seedlings?


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Re: coco in seedling substrate
« Reply #1 on: December 19, 2022, 12:22:48 PM »
If it just a Coco block then it should have no salt in it whatsoever

Have you googled the product/manufacturer?

The stuff I get in the UK is sold online by firms who seem to support the hemp growing industry ;) - you just add water, and it fluffs up to about 10ltrs - last time I bought some it was about £1 a block and I still have about 60 blocks in the shed

If I am using it for seed growing, I tend to mix it 50/50 with cat litter or 50/50 with perlite or 50/50 with vermiculite

Depends on what you are trying to germinate - it's good stuff - clean and weed free

"Never believe anything you read on the Internet" Oscar Wilde


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Re: coco in seedling substrate
« Reply #2 on: December 19, 2022, 12:42:28 PM »
Early coco fibre products had a reputation of being prepared in coastal/beach side premises; hence contamination with sea water and salt (NaCl) If you want to be sure wash it a few times with clean water before use; filtered rain water should be Cl free; but most mains water too I expect unless your water supplier is on the coast. Note most water softeners use salt if you have a softener in the house.
Edge of Chiltern hills, 25 miles west of London, England


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Re: coco in seedling substrate
« Reply #3 on: December 19, 2022, 06:56:24 PM »

It should not contain salt, but you can wash it to be sure.

There are several options for 'how to use it:

1) It can be used as a planting medium similar to orchid bark. In this case you need to add all plant nutrients as in hydroponics.

2) It can be used as a substrate to prevent soil caking or drying out between waterings.

3) It can be used as a soil amendment to keep soil from caking and improve water retention and drainage

Marc Rosenblum

Falls City, OR USA

I am in USDA zone 8b where temperatures almost never fall below 15F -9.4C.  Rainfall 50" 110 cm + but none  June-September.  We seldom get snow; but when it comes we get 30" overnight. Soil is sandy loam with a lot of humus. 
Oregon- where Dallas is NNW of Phoenix

Véronique Macrelle

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Re: coco in seedling substrate
« Reply #4 on: December 19, 2022, 07:20:14 PM »
thank you very much :)

Vinny 123

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Re: coco in seedling substrate
« Reply #5 on: December 28, 2022, 12:42:21 PM »
Your taste is very sensitive to salt - break a small chunk off and taste or soak and taste the water - it only needs to just touch the tongue, then spit it out and rinse if you are at all concerned.

Certainly going back to the early days of coir for composts - that must be 30 years at least - there were warnings about salt content of products sold for anything but horticulture. I am unsure about how the fibre and the granules used for composts etc. are separated (coir fibre still has lots of commercial uses), but quite possibly the coconut husks were soaked in sea water as fresh water in areas that are producing coir is a premium product.


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