Composting Perennial Weeds

We are often advised that as perennial weeds will survive home composting using cold composting techniques, they should not be composted at home but put in the “Green” bin to be collected by the Council as part of their kerbside collections. This will mean that the weeds are hot composted by the council and can then be purchased back by the home gardener as part of commercially available composts.

However, in most cases there are two simple relatively quick  options available to the home composter faced with perennial weeds involving pre-treated to make them safe to be cold composted. These options include drowning and  desiccation.  Both of these techniques can be seen at the Leicester Stokes Wood Allotment Composting site.

Drowning

Drowning is one of the quickest ways of dealing with perennial weeds and it has the advantage of producing a compost activator that can be added to the compost bin or used as a liquid plant food.

The perennial weeds are put into a lidded bucket, old Bokashi bin or water butt depending on the quantity involved and weighed down with a brick or stone. The weeds are covered with water, the lid put in place to exclude light and the soup left for four weeks. The liquid is then strained off to be used diluted and used as a plant food (see  Plant Liquid Feeds) with the sludge being added to the compost bin or the complete contents of the bucket can be added to the compost bin.

Drying

This method requires a hot sunny summer to work most effectively.  Spread the perennial weeds, or their roots, on a dry flat surface such as a concrete paving slab in full sun.  To be on the safe side, if there are not too many of them,  I like to smash and flatten them with a club hammer at this stage to assist the drying process.  Once smashed they can be left on the concrete slab, moved to dry on a wooden cover on the top of the compost bin if a New Zealand or pallet bin is being used or dried on a rack made of discarded plastic bread crates (see photo).  After two or three weeks in hot sunny weather the roots will be sufficiently  baked to be  safely added to the compost bin. If damp and dry the time should be extended. 

More techniques are given on the www.carryoncomposting.com     perennial weed page

Beehive compost bins are often chosen for use in small gardens where the bin will be highly visible as  they look more attractive than conventional plastic bins. The early bins tended to be small, as where the gardens in which they were to be used and were sometimes criticized as being too small to work effectively. However, they are now available in a variety of sizes.

 On our Stokes Wood Leicester Composting site, we have chosen to use one of the small bins  a 211 litre Rowlinson Beehive, donated by GardenSite.co, comparing it with the most popular small plastic bin the  220litre black Compost Converter provided under the Council subsidised scheme.

The Blackwall 220 Litre Black Compost Converter was voted best "Budget Buy" in Gardeners' World is the UK's best-selling home compost bin. It has sold over three million sold to date. It is made out of  UV stabilised recycled plastic. This is a low-cost entry-level bin and does not need assembly. It has a removable lid which can be a little tight to remove when the empty bin is first installed. The plastic bin is quite light and needs to be set into the ground to prevent being blown away when it is empty. I must declare an interest here for as a Master Composter I have been promoting Compost Converters for years as a good entry level bin and have owned six of the large 330l bins at home and on the allotment.

Wooden Beehive compost bins are relatively expensive,  but this is the price of buying a garden feature rather than just a compost bin. The model we are testing  has to be assembled but the instructions are easy to follow  and gave no problems. It has a hinged lid with a support to hold it open. Being wood it weighs more than the plastic bin and is less likely to be blown away in strong winds.

We started both bins with approximately the same amount of garden waste and over the next month or so will be cold composting garden waste  adding  waste in small quantities as it become available. The photo shows the two bins side by side

Stokes Wood Ament Composting Demonstration Site

Work has started on putting a concrete path round the front of the plot so that visitors can gain access from the entrance to the outdoor seating area  for the pavilion. Once this work is completed most of the plot will be covered in woodchip  to provide an environmentally friendly surface, clean surface that can be kept weed free.  This surface will also be provided for the tumbler bins and  the area round the raised beds.

The pallet  and plastic bins will be on cultivated area of annual  flowers to add colour to the site while providing easy access to the bins.

Stokes Wood Allotment composting demonstration site. More "greens" left in the Reception bay for the composting today. The first batch was added to the two Hotbins while the rest was shared between the cold composting bins shown in the background of the photo. 

The Jora food composter is also ready to harvest. Photos are available at http://www.carryoncomposting.com/142941482

We are on track to have a good supply of compost for visitors to the Compost Awareness Week Open afternoon on 5th May to make Seedbombs and enjoy a good Compost Safari. Visitors in advance of the Opening date are welcome on Wednesday mornings. Cooked breakfasts are available for only £3

The www,carryoncomposting page on Rats in Compost Bin (http://www.carryoncomposting.com/416920198)  has been updated to include more information on Leptospirosis (Weils Disease). A shorter version is given below 

Leptospira is spread in rats' urine and can survive in water for several months  which plays an important role as a source of transmission of leptospirosis to man and other animals.  There is a small risk of catching Weil’s Disease from contact with soil or compost contaminated by rats but by far the highest risk is to  farmers and vets is from contact with infected urine or blood followed by  fishermen, water sports enthusiasts following contact with  contaminated. 

While in the UK the risk to humans is small, with  less than 40 cases reported in England and Wales every year  it is probably a good idea to wear gloves when handling garden compost and  to cover cuts or grazes and to reduce the risk of contamination of compost by rat urine .

 Temperatures below 4°C and above 37C° will kill Leptospira which has an optimum temperature of  25˚C, needs  a moist atmosphere and a  pH near neutral. 

In general compost does not present a problem as even if rats have contaminated the bin. Once the compost is applied to and mixed with the soil, the level of bacteria will be so low  that vegetables grown in it will be safe to cook and eat as normal. However, if  a cold compost bin  or heap is known to have been rat-infested it might be advisable to use the compost  in the flower garden or as a mulch round established trees. It is best not to use it  round low growing  fruits or vegetables that are going to be eaten raw and the edible parts may be in contact with the soil or compost e.g. radish, celery, cucumber, strawberry.

Vegetables, fruit and  herbs should always be washed  Temperatures below 4°C and above 37C° will kill the leptospira bacteria.