Wednesday, 30 July 2008

shredded woad

Helen, who is growing most of my woad for me, emailed a bit despairedly on Monday. Slugs being the main cause, and her concern that I wouldn't have any leaves left come harvest time. I popped over that afternoon, the following photos are from that visit. These first four show various stages of shreddedness... but most plants were doing just fine.

And so... slug control: Helen has access to sawdust, I have access to coffee grounds so we are trying both. The coffee was applied just before this photo around up-till-then unprotected plants. Most successful seems to be a copper ring (top and bottom right), but only a few plants have these, and only one has broken eggshells (white). Research suggests that coffee grounds release nitrogen into the soil, an element apparently loved by woad - or rather its uptake increases eventual pigment quantity. I've also read that coffee grounds have an anaerobic effect if applied too thickly, and that it's either acidic (which can't be too good when your soil is already acidic) or breaks down to neutrality (which shouldn't matter). There is more to consider though than woadish preference - nitrogen broken down by bacteria forms nitrous oxide (N2O), a far more potent greenhouse gas than carbon dioxide. Not being a chemist I'm really not sure of the pros and cons of using it as slug repellent and soil fertiliser, or even of growing nitrogen-loving woad itself... but I will find out! At least the coffee grounds (like the sawdust) are already waste products that would eventually decompose anyway.

Helen has created three plots for the woad. The first is in a spare part of her raised walled veggie garden - I think she said courgettes were growing there until the slugs got 'em. The next is a raised bed that last grew potatoes; and the third is part of the bank that had been covered by carpet to kill couch grass (roots were dug out before planting). All sites get loads of lovely sun... and rain, it being the Cornish summer holidays now.

And finally, four of my five potted plants. Three are teenagers now and allowed out all night but the fourth (back left, in ceramic pot) is still a kid and comes in around midnight. A few days ago I came home feeling so unwell I didn't have the energy to bring it in... and yes, the slugs took advantage. But it's still growing. The fifth plant is elsewhere with the tomatoes and aubergines, a different mini-climate, so I can see how location changes growing patterns. All of mine have had coffee grounds protection from their first venture outdoors.

Wednesday, 16 July 2008

cost of boiling out wax an interim stage of wax removal in the Feeding the Ducks batik:

Ten litres of cold water in the Burco took 23 minutes to reach boiling stage, and the (metre square) batik was submerged for a further 22 minutes with the power intermittently on. The total 45 minutes 'boiling out wax' activity used 1.4 kwh of electricity. Translating to 0.6 kg CO2.

Starting with warm or even room temperature water would have saved a little energy, but more would have been saved if the batik hadn't needed to boil for so long. Sometimes a few minutes dip is enough to melt and remove wax but other times the wax leaves a yellowish residue that takes longer to shift. It's often only visible when the batik is wet but can affect subsequent dyeings, such as had had happened with this last dyeing.

Experience suggests this happens when wax has been 'well cooked', turning brown, and where used has lost some ability to repel water/dye. In turn, being well cooked could mean the wax is being heated too high, ie where it touches the hottest part of the bowl it's getting hotter than ideal. But if I have the pot at lower temperature then the wax isn't hot enough for fast canting work.

I removed the 'old' wax, cleaned the pot and replenished it with new wax to the same recipe (100 g batik mix, 20 g white beeswax). This time I used half quantity, ie half filling the pot and heating at setting '5'. Always before I've filled the pot to ensure a consistently heated supply of wax, but my thinking now is that if there is less wax to start with then the pot needn't be set so high to get the ideal wax temperature. The wax is both less likely to be 'cooked' on the hot part and - importantly - used up by the time replenishment is needed!

I am truly shocked to find that of the 240 g of wax heated last time round, 145 g was removed too 'well-cooked', meaning only 95 g was used for the batik. I have been very very wasteful of resources and am determined to get this amended.

Another thought I had for saving energy with boiling out wax is to insulate the Burco boiler. Followed by hesitation from the likelihood of getting the insulation both very wet and coated by molten wax spluttering over the Burco top. And from remembering the hint from Paul Mobbs that beyond a certain depth (0.2m) loft insulation becomes carbon-uneffective (production etc cost outweighing savings). But, in my loft some old futon cotton-wool sheets are stored some of which might be adapted for this purpose.

This Ducks batik has already required three or four interim boilings out, and will need two or three more before the end. I don't usually work like this, believing it goes against the nature of batik if you can't go forward with the design in one go, with only one boiling out at the end. Somehow this design got too complex. I will be glad when it's finished!

images: top - over-cooked wax; middle - new wax pellets half filling wax pot; bottom - interim stage - Feeding the Ducks batik

Wednesday, 9 July 2008

energy update - and carbon panic!

The Beeb's online news states that a Brit's annual carbon emissions are 2.67 tonnes (US 5.6, China 1.1, India 0.3, Kenya 0.1). My latest electric stats showed 2.8 tonnes for the year - how could this be? How could I be using more than the average person just on electricity alone? How had I not sussed this before? Further research makes the difference between carbon emissions and carbon dioxide emissions apparent...

Average UK emissions of CO2 were between 9.1 and 9.5 tonnes annually in 2005 (see here and here, both quoting from same source), which translates to 2.6 tonnes carbon annually per person. I was relieved not to be worse than average, but not for long... Monbiot's article reminded me that the goal is reducing to about a tonne of CO2 equivalent pa. There's a long way to go.

My electric usage seems to have stabilised at 2.7 to 2.8 tonnes CO2 annually (to work out yours multiply your total kwh by 0.43 for kgCO2, then divide by 1000 for tonnes CO2. Or see Carbon Trust for more info). There's not much more switching off of unused or unnecessary appliances and lights, or other chipping away I can do. It's time for substantial changes... and investment.

A joiner has advised that all my single glaze windows can be converted to double glaze - they are well-made wooden windows, only 14 or so years old and in good condition. I'm just waiting for the quote now. The past two years I'd put up temporary double glazing film, like polythene taped to the frame, and they made such a difference to heat retention that double glazing is a must. Can't think why I've delayed so long (other than house selling intentions). The studio has had lined curtains as well as blinds for the past two years, and a thermal-backed blind arrived yesterday for the (double glazed) skylight. Before the winter I want to get lined curtains up in every room.

But still all this won't be enough. Especially if Peak Gas is on the horizon, never mind Peak Oil. Paul Mobbs, whose talk on Energy Beyond Oil I went to last week, suggested 58% of domestic energy consumption goes on space heating, with water heating at 24%, lighting and appliances at 12% and cooking at 6%. My house is all electric, heating is from storage heaters (two modern, one old) with a blow-heater in the bathroom and for back-up. As I work at home they seem practical, place is nice and warm for starting work in the morning. But I have two lovely open fireplaces (sitting room and kitchen), desolate without woodburner or (wood-fired) rayburn. Apparently woodburners make storage heaters less effective - as one starts cooling down at night, the other is gauging how much work to do to get and keep the place warm - and can't help but get it wrong. Can only be one or the other. But I'm going to investigate this further... if power rationing kicks in in a few years time it's good to have an alternative ready! And I like the idea of (slow) cooking or keeping the kettle warm on top. There's also an innate good feeling from seeing/hearing flames.

Solar hot water is another option to investigate. But the shower does its own heating (very practical this time of year when luke warm is all that's needed - a luxurious 15 minute shower uses less than a unit), and there are no radiators to fill. It would be good for boiling out wax of course, but other than washing and washing up there aren't many other needs for hot water. Cooking? Coffee?

Think I'll concentrate on curtain lining and double glazing this year, and (unless I've moved) come back to technological matters next year.