Yes it’s that time of year again, when I make up a hot bed (or homemade ‘hot box’), ready to help propagate heat-loving seedlings such as tomatoes and peppers. We put the frame back in the Little Tunnel a week or so ago so the wood could dry out after standing out in the cold for months; and then today I filled it up with barrow-loads of fresh horse manure, soiled straw and wood shavings from the nextdoor horse stables. I added a bit of water as I went, just to ensure that the straw wasn’t too dry for all that lovely biological activity to happen. Then I turbo-screwed in the ply-wood front, filled the frame up to the top with more manure and straw/shavings, and finally placed the old recycled door on top which acts as a lid/bench top for the module trays to stand on. Hopefully in a few days the heap temperature will have crept up to around 60-70C, then started to drop down again; to leave us with a nice warm 10-20C continuous heat for sowing the seedlings next week!
It’s surprising how tired you can get, hefting shovel-loads of horse poo around, isn’t it? I spent a few hours this afternoon spreading the lovely piles of rotted-down horse manure that Richard the farmer had plopped on the field for me with his front-load bucket (stop sniggering at the back) on the tractor. He also managed to spread it around quite a bit, using the back of the bucket and tractor tyres; but there were still a few piles of it that needed to be spread a bit more, to give a more even manuring to the patch, and also to try and dry it out as much as possible before I attempt to go through with the rotovator.
This patch is 1 and 1/2 of the patches from last year; where the carrots, parsnips and fennel were, and also where the leeks were. This year I am taking on a bit more land near the polytunnels – this new bit will be divided into 2 patches (brassicas & leeks/legumes); so the old field will be divided into 3 rather than 5 sections, to fit my 5-year rotation. The manured patch will be home to squashes, pumpkins, courgettes and beets this year; then go down to green manure in the autumn for next year. The other patches will be green manure (mostly established last year), and then where the brassicas where, I’ll put in the carrots, parsnips & fennel.
Talking of poo, the hot bed made of fresh manure has been doing well – I recorded on 63C just below the surface on 5/3/15 (air temperature around 10-18C); 28C on 11/3/15; 40C on 13/3/15 (when it was pretty cold outside and not sunny, around 5C); and now seems to have settled at around 20C. The tomato seedlings and potted-on peppers are now nestled inside the hot bed, on a mini pallet, now that the tempature has settled down; so hopefully this will protect the seedlings even more from any chilly drafts coming through the polytunnel doors.
We had a pile of pallets mounting up from around the farm, from the various enterprises here (general farm & farm shop deliveries, Bath Bespoke carpentry, Easy José coffee, not to mention The Oven bakery, Young Blooms florists and Willy Good Ale) – along with all my veg, fruit and herbs, soon we’ll pretty much have everything here you need to avoid the supermarkets altogether!
So I dismantled a load of pallets using a pry bar and reused the wood to build 2 sides of the hot-bed; screwing or nailing the long pallet wood into the thicker shorter planks from underneath the pallets. I’d found a large sheet of scrap ply wood used as pallet separators, so thought that would save me stripping another pallet to make the 3rd side, and used that instead; plus I’d saved an old wooden door from the carpenter’s scrap pile a few months previously, which slotted into position and just about made the moveable 4th side.
The 3-side C-shape of the bed went into the top of the Little Tunnel (just about fitted through the doorway sideways), on the bare clear soil (the mustard stumps in the pictures came out before loading the bed up); then I could start filling the box up with horse manure. Farmer Richard had kindly dropped a whole bucket-load of fresh strawy manure next to the tunnel over the weekend, so I set about trundling 15 wheelbarrows-full into the box. I’d also been left some spent hops from the Willy Good Ale guys (I have used these previously to mulch the raspberries as an experiment, and also dropped some in the compost); so I though I’d throw some of these in the hot bed too, to help the fermentation of the straw and manure, and general break-down of materials by bacteria and others, which is what gives off the heat. Mind you I’ve not heard of this being done before; and there may not be too much potential fermentation left in the hops, so I only put a few sprinkles in. The nice chaps at Carbon Gold have also offered to give me some GrowChar soil conditoner, to trial some in the hot bed and elsehwere (full of mycorrhizae and other exciting things that the microscopic fauna and flauna in the hot bed should love), so when that arrives I’ll pop a bit in there too.
After several tramplings down, and a few watering cans full of rainwater sprinkled over the layers to keep things nice and moist, and therefore in peak composting condition, I placed a thin pallet top over the whole bed with some empty compost sacks on top (to keep the moisture in the hot bed on one side, and leftover irrigation water under the seed trays on the other); then brought in the tomatoes, plus a tray of broad beans, all sown on Friday 27th – the broadies are partly to trial against the other broadies in the Module Tunnel, to see if germination is any quicker/better. Plus it gives me more room in the module tunnel for when the next mega batch of sowing happens in the next few weeks.
I popped a compost themometer in the hot bed too, to keep an eye on approx temperatures there: on Monday (approx 7-8C) the soil temperature in the tunnels was around 11C; the air temperature in the polytunnels was around 20C (nice sunny day); and the freshly made hot bed was 9C (the material had been outside in the cold, and was waterered with cold rain water). I’m keeping my fingers crossed that the temperature rises soon…