Plastic Colours

I now have an amazing seven thousand people on the Raised Vegetable Facebook page. I actually thought it would stop at 5 thousand but the requests to join just keep coming. Everyone that joins are either in America or Canada which makes it a bit awkward as some people are harvesting their salads whist others are still shovelling snow off their paths. 

As fun as this page is I don’t think it will last long unless I get another moderator to keep things going while I sleep.  I’m finding the job of moderator a bit time consuming. People are being very good though, it’s my own issues I have to address.

I have quite a few people asking questions, which is why the page is there I suppose. There are some questions that can be answered by just Googling the keywords. For example someone asked a question about tomatoes. I sent them a great little website called “Let me Google that for you (lmgtfy.com)” which does exactly that, without you having to type on the page (Google it for a better description)

I thought it was funny and would give them a giggle. How wrong I was!  I had a torrent of abuse and had to look up some of the words they were calling me.  I duly deleted the comments and banned the user permanently.  

It was all too easy to delete the person and I must confess the power went to my head. I started banning anyone that wavered from the topic of raised beds. The problem was that the topics they were posting were proving to be very popular (even pictures of cats were getting likes). 

My lad walked past me and sorted the situation out immediately with two suggestions. Firstly for me to stop being a power crazy control freak Facebooker and secondly to sit back and let the members decide what’s acceptable or not.  I soon know if someone is trying to sell sunglasses on the page as people report the posts for me to delete. So I now let the readers and contributors decide and I sit back and take deep breaths. 

Reflections

One issue that came up this week was about the use of mulch. Natural soil coverings are well documented here but a lot of gardeners are moving to plastic coverings. I don’t like the idea of putting something on the garden that isn’t totally biodegradable but it looks like some of our friends over the water don’t feel the same and are opting for this type of ground cover.

Plastic covering differ by their opacity (how much light will pass through the plastic) this will govern both the amount of radiation which will heat the soil and the growth of weeds under the film. The colour - black, white, silver, red, blue, brown, IRT (infrared thermal), green IRT and yellow all produce specific temperature (both soil and ambient) and light modifications within the soil and air.

Over the last 10 years Penn State Centre for Plasticulture has conducted extensive testing of the effect of mulch colour and various vegetable crops. 

Some generalities that can be made regarding colour are:

• Silver repels aphids.
• Blue attracts thrips - has been very effective in greenhouse tomato production.
• Yellow attracts insects. (You’ll know that if you ever wear yellow in summer!)

There also appears to be some reduction in disease pressure with crops grown on specific colours.

Tomato - appears to respond more to red mulch compared to black with an average 12% increase in marketable fruit yield over a 3 year period. There appears to be a reduction in the incidence of early blight in plants grown on red mulch compared to plants grown on black mulch.

Pepper – appears to respond more to silver mulch compared to black with an average 20% increase in marketable fruit yield and fruit size over a 3 year period.

Cucumber - appears to respond more to dark blue mulch compared to black with an average 30% increase in marketable fruit yield over a 3 year period

Summer Squash - appears to respond more to dark blue mulch compared to black with an average 20% increase in marketable fruit yield over a 2 year period

Onion -appears to respond more to several different mulch colours including red, metalized silver and black compared to no plastic mulch with an average 24% increase in marketable bulb yield over 8 varieties.

Potato - appears to respond more to several different mulch colours including red, metalized silver and black compared to no plastic mulch with an average 24% increase in marketable tuber yield.

It’ll be interesting to see if coloured bark chips will give the same results. I for one know I will not be spending 10 years doing the study. I’m too busy moderating the Facebook page.