Improving your soil and plant growth with comfrey feed.

 Improving your soil and plant growth with comfrey feed.

Plant fertilisers such as Tomorite or Chicken pellets are getting increasingly costly to buy and sourcing suitable manure and transporting it to the farm is hard work. Increasingly at HCF we have become aware of the potential of growing our own fertiliser- Comfrey. When Andy Waterman first proposed growing it around the Old Fruit cage several years ago there was opposition from some team leaders, so we grew it in large pots for a few years before planting a small comfrey patch near the strawberry polytunnel. Demand for liquid fertiliser is increasing as are the potential uses and so the places where we are beginning to grow it are increasing.

Bocking 14 Comfrey 

Why is Comfrey so useful?

Leafy vegetables need lots of Nitrogen , Root vegetables need lots of Phosphorus (P), flowers and fruits need lots of Potassium (K). Or as Gareth Evans, my old Botany lecturer would say

“N for shoots, P for Roots, K for fruits.”

Comfrey is as good as Tomorite for plants such as tomatoes, peppers, and beans as well as greedy feeders like potatoes plus fruits such as strawberries, gooseberries and raspberries as the table shows.

In addition, it compares well with manure and compost:

One square metre will produce around 7 kg of comfrey a year which can be cut three or four times during the season and so a large biomass of plant material can be produced from a small space. The wonderful benefit of Comfrey is that it has extremely long roots which can mine nutrients from several metres below the surface and which would otherwise be totally unavailable to vegetable crops. The disadvantage is that once comfrey is growing the roots are difficult to kill off and the plant lasts for over 20 years. So don’t ever plant comfrey in a place if you might sometime later want to move it somewhere else.

How to grow comfrey.

We use a variety called Bocking 14 (developed in Bocking, Essex) which is a sterile hybrid clone of two Russian forms. Bocking 14 doesn’t set viable seed, but does spread slowly if not checked back. To make more plants a plant is cut up, the leaf removed and the stem and upper area of the root cut into small sections a few centimeters long.These are allowed to grow roots and leaves in a pot containing a light compost. The young plants are planted out into a cleared area of ground where they are expected to grow. Planting distances are approximately 60 cm between plants.

Comfrey growing along a fence line made of old pallets

How to use comfrey

There are several ways to use Comfrey.

Rotting comfrey at the bottom of a bucket

Toby Turl has recently introduced a new method of makes a concentrated liquid feed. He cuts the leaves and puts them in a bin with a hole at the bottom. As the comfrey breaks down liquid drains through the hole into a small container below which collects the concentrated liquid. He makes a litre every couple of weeks and this is diluted about 10 times over before being watered on plants.

Adding comfrey to a compost bin to speed up composting

I cut comfrey leaves, mixing them with pernicious weeds (nettles, couch grass, docks, dandelions and thistles) and toss them into a sack in an old rubbish bin which has been filled with water. After a few weeks when I need some liquid feed I push my watering can into the bin, draw up half a can full of liquid, dilute it further with water and pour onto my fruit bushes. After a couple of months all the comfrey and weeds have broken down in the sack, so I draw out the liquid for use on the plants then tip the completely dead slime into the compost bin or onto a plot. This is a much speedier method than cold composting and there are no viable seeds or pieces of root which will find their way back onto the soil.

Another use for comfrey is as a surface mulch on blackcurrants and raspberries. I use the “chop and drop” method. First chop your leaves, then lay a 5 cm mulch of the leaves on the soil around the plants. Within a couple of weeks the leaves will have gone black and within a month they will have disappeared completely. This mulch slows down evaporation of moisture from the soil and suppresses weeds. As the comfrey leaves wilt they attract slugs and snails, possibly from feeding on surrounding valuable plants and so reduce damage. Hopefully then, the slug will be devoured by a hungry ground beetle or blackbird.

So there are several ways in which we can use this most helpful of plants on our community farm.

 

Improving the soil with leaf-mould

 

Anyone who lives in this part of Great Britain knows the problems created by leaves at this time of the year. Yet they can be of great value if used wisely at the farm or in your garden or allotment.

Why is leaf-mould useful?

 It’s not that leaves have great nutritional value. The tree tends to suck the nutrients out of the leaves before they drop them. Well-rotted leaf-mould greatest benefit is as a soil conditioner, improving the structure of a soil, rather like peat, but without the damaging environmental costs of extracting peat. Leaves tend to have a high Carbon:Nitrogen ratio, averaging around 50:1 and low levels of essential nutrients: Nitrogen 0.66-1.62%, Phosphorus 0.02-0.29%, Potassium 0.09-0.88%.

Leaves also contain useful amounts of Calcium and Magnesium.

How do you make leaf-mould?

First brush up your leaves or rake them off a lawn. We actually collect several wheel-barrow loads from our road. Then there are several options for making use of it;

1.     Store leaves in bin liners. Moisten the leaves if they are dry and prick holes in the bag. Tie loosely, pile up the bags and leave in a quiet spot for up to two years.

2.     Build a chicken wire frame in a hidden corner of the garden about 1m³ and pile up with leaves. Turn the pile occasionally. (See the frames at HCF).

3.     Store in an open topped barrel or compost bin with drainage holes at the bottom for up to 2 years.

4.     Put layers of leaves as your brown material in a compost bin and alternate with green material such as grass clippings, weeds or food waste.

5.     Cover frost sensitive plants which die back in the autumn to protect the plants from winter rain and frosts. You can make a wire frame around a plant such as a banana after the trunk has been cut off, then pack and insulating layer leaves around the stump and cover the stump with a plastic bag.

Which leaves are best to use?

Leaves that will quickly break down include: ash, beech, birch, cherry, elm, hazel, lime, hornbeam, and willow.

Laves that slowly break down include: hawthorn, maple, magnolia, oak, sycamore and horse chestnut.

The best leaves to use are oak, beech and hornbeam.

Evergreen leaves should be shredded first as they take a very long time to break down. They include: holly, bay, rhododendron, photinia and skimmia.

Conifer needles take a very long time to break down even if moistened and turned every few weeks, so they are best used as a mulch over acid loving plants such as blueberries and azaleas.

How do you use leaf-mould?

Some plants such as vegetables, annuals and grasses prefer soils dominated by bacteria so it is best to use compost or well-rotted manure as soil conditioners for these groups. The bacteria quickly break down the organic material which generally has a higher level of nutrients and a lower C:N ratio. Leaf mould contains lower nutrient levels plus lots more carbon locked up in complex substances like starch, lignin and cellulose which fungi tend to slowly break down. So leaf-mould is better used on trees, fruit bushes, shrubs and perennials which prefer soils dominated by fungi. Well rotted leaf-mould should be added to the soil surface of these groups as a mulch in the autumn or spring to help build the soil mycorrhizal fungi. The mycorrhiza will bring more water and nutrients to the plant roots and so help to create stronger, healthier plants.

An alternative use of leaf-mould is to dig it into the soil when it has been partially broken down to raise the humus content of the soil. This is especially useful for heavy clay soils or light sandy soils. As well as improving soil structure by providing more food for soil living organisms it will help the soil to hold more water to enable the plants to tolerate drought better and hold more nutrients bound onto the humus.

Finally leaf-mould can be mixed with sharp sand, garden compost and soil and used as a potting compost.