Wednesday, September 29, 2010
Baby It's Hot in There!
There are lots of videos on line about compost but this article gives a simple recipe if you want to spend a few hours making "Hot" compost this fall to take advantage of all the veggie greens you are pulling out. This hot compost recipe allows you to build a pile that is ready in a hurry. No need to replace your existing pile(s) - this is something extra - a fast pile to get the extra stuff in the garden fired up and disintegrated in a hurry. Estimates say you can build and finish a fast compost in just over a month. It will heat up right away and with turning it will be ready before Halloween.
1- Day 1. Gather fresh green materials. I asked my local landscaper to drop off other people's grass clippings- he left about 2 yards of stuff on a tarp last friday. He says he has not sprayed herbicides on these lawns - they have only been fertilized. I also stopped by a local riding stable and grabbed a feedbag full of really fresh horse manure. Manures are real fire starters and I really wanted to get this pile going fast.
2- gather brown materials such as old weeds, piles of things that are dry and not decomposing and fine wood shavings if available. I always have plenty of these things laying about and since I am planning a hot pile I am not worried about weed seeds. The seeds and any pathogens should be wiped out in the heat.
3 - start piling materials in about 6 cm or 3 inch layers beginning with a stack of dry stuff followed by a stack of green. You are trying to get equal amounts of dry and green (carbon and nitrogen) stuff but remember a wood shaving has 1:200 nitrogen to carbon while grass clippings have 20:1 nitrogen to carbon. You need equal amounts of carbon and nitrogen in the end so you have to guess how much of each item to add. I err on the side of adding too much nitrogen.
4 - make the pile large or at least a cubic meter in size so that once it gets hot it will be big enough to hold the heat, I try to make the base wider than a meter so that the inevitable sloping sides will leave it at least a meter wide and high.
5- water the pile so that it is damp - not soaking sopping wet but damp throughout. If it threatens rain cover the top with a tarp. I leave the sides open for airflow.
6- hope for the best. You want 55-70 degrees C within a few days. And you want to maintain this for about three days. I have a thermometer I bought at Lee Valley Tools and it only reads in F but my husband translated for me.
7- Day 2-3. Results have been fabulous. On the first morning I had 140 F already. This is about 60 C so it is right on the money. So far it has been three days and the pile is still smoking hot. Exciting stuff for a gardener. If it was to get hotter I would water it or turn it because over 70 C and the stuff won't be composting properly. I have not had that problem yet. Like an emergency room nurse I keep slipping outside, checking the temperature of my patient several times a day.
8- Day four - the pile has been hot for three full days. After three days at this temperature the weed seeds and most of the pathogens are toast but the outside of the pile didn't get that hot. It is time to turn it. It is heavy so I have asked for help. Thank-you dear husband. This is essentially why I don't do this often. I have a turning composter for making the most of my greens and browns. But because the turning unit is only four cubic feet it is not big enough to sustain a high temperature. When I am doing really well it is heating up around 90 degrees F. This is only in the 30's C.
9. Success- the turned pile is back in the "pile" shape and is about 1 meter tall and wide. After turning it to incorporate the fresh looking stuff on the outside into the center of the pile I take the temperature again. It is now 100 C - which is considered in the Steady zone. I might add a bit more water and put the tarp back on to hold in the heat because I want to get it back up to 140 degrees again for another three days.
10 Day 5 - the temperature is back up to 140 F. I have not watered it but it may be getting dry so I will be keeping an eye on it. I wish I had added phosphorus to tie up the nitrogen. Rock phosphate is the best choice here, I usually add rock dust too but was in a hurry and forgot that little detail. Okay in two more days the pile can be turned one final time and then left on it's own to finish.
11. Meanwhile I have started a separate leaf pile with 1/2" hardware wire - 3' tall. It is not tied together. The leaves are holding the shape. I am only going to make leaf mold so am not adding anything to the pile to make it hot- not yet anyway.
12. Day 6 - wow! Second day since turning and temperature has shot right up to 150 F this morning - good thing I didn't water it. If it gets any hotter I may need to water to cool it down. According to my estimates it needs another full day at this temperature and then we'll turn it one last time and leave it. Its cool to be hot.