Your Questions Answered

Q.	Isn't bark an expensive ingredient?

A.

No, not when full account is taken of the increase in quality which can be obtained when using bark, the decreased risk of winter losses due to waterlogging in poorly structured mixes and the lack of slumping in the pot. Also many growers find that the number of pots filled by a given quantity of compost increases when bark is used. Melcourt Potting Bark is fine-free which means that the entire volume purchased goes toward structural opening of the mix, unlike other brands, where the relatively high volume of fines tends to negate some of the positive effects of the coarse fraction. See The Cost-Efficiency of Melcourt Grower Barks.

Q.	Do I have to add extra nitrogen when using bark in my compost?

A.

For most except ericaceous and other salt sensitive crops, the answer is yes. However, a small, straighforward addition of ammonium nitrate (eg "Nitram") at the time of compost mixing is all that is required. Extra nitrogen is not required in propagating composts. See Guidance Notes for full details.

Q.	Is bark difficult to re-wet once dried out?

A.

Bark is similar, and certainly no worse than peat if it is allowed to dry out. However, like peat it is very compatible with wetting agents and responds well to their use. If the compost has been allowed to become very dry, then a single drench with a wetting agent is usually all that is required to wet the compost up again.

Q.	Have Melcourt's barks been properly composted?

A.

We purposefully do not "compost" our grower barks as this leads to structural breakdown. As the usual reason for using bark in a growing medium is to improve structure, we believe that it is inappropriate to do anything to lessen this property. However, what we do ensure is that the process of maturing which all our growers' barks are put through, is thorough and fully checked by our rigorous quality assurance system. "Maturing" differs from "composting" in that the bark is stacked for a much shorter period, with much less turning. However, temperatures in excess of 50ºC are nevertheless achieved, which is enough to ensure the killing of any weed seeds, or other pathogens which may be present in the raw bark

Q.	Are there enough supplies of bark and Sylvafibre® to satisfy the potential market?

A.

Yes. Forestry Commission projections, based on the figures for new forest plantings over the last fifty years, indicate that the quantity of forest bi-products is set to at least double in the next ten years. Additional quantities of bark are being imported from Europe, to meet current market demand.

Q.	Are there any environmental problems associated with the use of bark or Sylvafibre®?

A.

All of Melcourt's bark products and Sylvafibre® are manufactured from parts of the tree which were formerly considered waste bi-products of the UK forestry industry. They are all sourced from forests which are managed on a fully sustained basis, and are all replanted as soon as the previous crop of timber is removed. Melcourt has depots strategically located around the country in order to reduce haulage between production sites and customers. The inclusion of bark or Sylvafibre® in the growing medium, even at a low level of 25% for example, does reduce the uptake of peat, which is a potential selling point if reduction in peat usage is important to your customer. See the Melcourt Environmental Policy Statement for further details.

Q.	I am not convinced that there is any product which can fully replace peat. Would you agree?

A.

Peat has been the staple ingredient of British loamless growing media for forty years or more and as such has been the subject of a continious process of research and development by government and commercial bodies alike. The quest to find products which can replace peat has, if anything, highlighted how valuable and versatile peat is. However, it is worth remembering that in countries which do not have their own reserves of peat, equally successful media have been developed over the years with other materials, such as bark and woodfibre. Using much of the methodology developed for peat, and by staying rigidly close to the criteria that any alternative would have to be as technically effective and as competitively priced as peat, Melcourt has developed Sylvafibre® and Melcourt Growbark®. Trials have proven that plants of a quality similar to or better than those raised in peat can be obtained, at a price very competitive with peat. As with peat, the research and development process continues, in order to expand the range of uses to which Sylvafibre® and Melcourt Growbark® can be put, but in the meantime, they are tried and tested products which growers can use with confidence.

Q.	I want to move towards peat-free production, but am worried about changing overnight. Can you help?

A.

Yes. Sylvafibre® and Melcourt Growbark® are compatible with peat, but are also designed to enable totally peat-free production. It is therefore possible to slowly increase the proportion of either Sylvafibre® or Melcourt Growbark® used in your peat-based mix, until you have gained enough experience with the product to be confident to move to a totally non-peat mix. Melcourt are able to offer qualified technical back-up to give you as much support as you need.

Q.	I've heard of "Bark Passports". Do they exist and what are they?

A.

As a result of an EC Plant Health Directive a wide range of plants and plant products, including bark, has to have a "passport" in order to move within the EC. To qualify for a passport the supplier must register with the relevant Plant Health Authority, which in the case of bark is the Forestry Authority, and undergo regular plant health inspections. The system was initiated in 1993 in order to help prevent the spread of pests and diseases and allows traceability so that any new infection can be traced back to the source. Bark beetles are the main cause for concern with the movement of bark. Melcourt is a registered supplier within this scheme, and all Melcourt Barks hold the relevant passport.

Q.	I've heard that it is possible to control fungal pathogens by incorporating bark in the compost. Is this true?

A.

There is a growing body of evidence which suggests that it is possible to control fungal pathogens such as Phytophthora, Pythium and Fusarium by incorporating a proportion of bark into the medium. Much research on this topic has been carried out in the USA and in this country the HDC has funded work which has demonstrated the effect. There is still some way to go before we can market bark on its ability to control pathogens, but at Melcourt we are convinced that this will become a reality in the future.