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Using Comfrey: Making Comfrey Compost, Comfrey Liquid Feed or Tea

Comfrey as a Compost Activator

Cuts of comfrey fresh or wilted can be laid onto the compost heap, layered with the weeds or grass cuttings. Comfrey is so rich that it can be used as if it was manure to activate a slow compost heap.

Comfrey for TeaA layer of wilted comfrey can be laid in the trench before planting potatoes. In fact this is the best use of the first cut of the year if it can be taken before planting time.

Wilted comfrey can also be laid between the rows when potatoes are growing. I would have expected this to encourage slugs but haven’t noticed any increased problem with slugs by doing this. Perhaps slugs don’t like comfrey much, they certainly don’t bother the plants once they’ve reached six inches high.

Adding layers of cut comfrey to a leafmould pile will add some nutrient value to the leafmould which is useful when making your own seed composts.

When growing tomatoes outdoors or in a greenhouse border, wilted and chopped comfrey will add 100% natural, organichigh potash fertiliser.

French and Runner Beans will benefit from comfrey in the planting trench or applied as a mulch.

Nutritional NPK Analysis of Bocking 14 Comfrey

L D Hills listed the following in his book Comfrey: Past, Present and Future

Comparative Nutritional Analysis of comfrey, compost and manure
Material Water
%
Nitrogen
(N) %
Phosphorus
(P) %
Potash
(K) %
Carbon: Nitrogen Ratio
Farm Yard Manure 76.0 0.64 0.23 0.32 14 -1
Wilted Russian Comfrey 75.0 0.74 0.24 1.19 9.8 – 1
Indore Compost 76.0 0.50 0.27 0.81 10 – 1

 

L D Hills did a more measured experiment of 14lbs of comfrey leaves in a 20 gallon drum (cited in Comfrey, Past Present and Future) and found the following results comparing with commercial liquid feeds made up to the manufacturer’s specifications.

Comfrey Liquid Feed versus Commercial Liquid Feeds
Tomorite Marinure Comfrey
Dry Matter 0.1410 0.0480 0.4090
Nitrogen (N) 0.0130 0.0070 0.0140
Potash (K) 0.0139 0.0019 0.0340
Phosphorus (P) 0.0093 0.0001 0.0059

How to Make Comfrey Tea

This is a makes a ready to use liquid feed, an ideal substitute for commercial tomato feed (except you might need to add a teaspoon of Epsom salts per 5 litres to provide magnesium)

Take a 100 litre barrel with a lid or water butt and fill nearly to the top. Put six or seven kilograms of comfrey leaves, wilted for a day and roughly chopped if you have time, into a hessian sack or, if you don’t have a sack, ladies tights or even an old pillow case.

Press the sack into the water to get the air out and then place the lid on the butt and leave for two weeks in warm weather, possibly four weeks in cold weather.

Be warned, the liquid stinks like raw sewage as the comfrey decomposes. If you leave the lid off the surface will soon be covered in flies. Whilst it may be logical to have the barrel near the greenhouse, because of the smell I would suggest as far away from the house (and other peoples houses) as possible.

Draw off from the tap into a watering can and use as tomato feed. The reason for putting the leaves into a bag is that just putting them into the barrel will block up the tap in short order and you’ll have to resort to dipping the can into the smelly barrel.

Concentrated Comfrey Liquid Feed

This can be bottled and then diluted for use at a rate of 10ml per litre (1:100).

Take a barrel with straight sides, or a drainpipe capped at one end. Drill a small hole or holes about 10mm diameter in the bottom and use some broken pot pieces to cover so the hole doesn’t block. Fill with wilted comfrey leaves, preferably chopped and place a board on top[ cut to just fit in the pipe or barrel

The easy way to make this is to use the barrel as a template on a piece of plywood and cut on the inside of the line.+

Place rocks or bricks on the board to press the comfrey down. Over the next 3 or 4 weeks the comfrey will rot down and a brown smelly liquid will drip from the base of the barrel through the hole.

You can store this in bottles with a screw top for later use. Don’t forget to label the bottle and keep out of the reach of young children.

The residue from both the concentrate and tea methods can be used as a mulch for potatoes or tomatoes or on the compost heap.

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