If I had planned ahead I would have done solar pasturization by putting saran wrap on the top of a picnic cooler full of compost.  Since I didn’t plan ahead I did this instead:

Grilled dirt anyone? The oven bag makes it look kinda like a dirt haggis.

An oven bag full of  my best screened compost cooked well done on the gas grill.  I added about a quart of water so that it would all steam evenly, and punched a small hole in the top to keep it from building pressure – took about 2 1/2 hours to reach 170 degrees Fahrenheit.  The probe thermometer lets you be more efficient by not opening the lid.  Needless to say plan on just letting it sit there for several hours to cool.

If you only cook the compost you should be able to make 2-3 times this volume of sterile homemade organic potting soil by the time you add the other ingredients.

The oven bag looks no worse for wear and tear, and I don’t see why you couldn’t reuse it again – for dirt of course.  Next time though maybe I’ll do better and use sunshine instead of fossil fuel, but in the middle of January this worked pretty well without cooking dirt in the kitchen.

This is the rig that I use to screen compost – it works very well and is built out of scrap lumber and a piece of 1/2″ by 1″ galvanized wire mesh left over from building some rabbit cages.

The last time I painted the garage roof I gave my retired commercial wheel barrow a nice thick coating with the last bit of roof paint to keep from having leftovers.  It’s ugly, but it keeps it from rusting.

A simple efficient compost screener

Just work your compost around with a hoe and pull the big pieces off the back.  Toss them back  on to the compost pile when you finish.

Work it about and pull the big pieces off the back

In a few minutes you’ll have a nice bit of screened compost.

This already looks like potting soil

If you want to make sterile potting soil you have to pasteurize  the compost by heating it up enough to kill any organisms that it might contain.  I don’t do that, and I rarely have any soil related problems because I make my compost in such a way that it heats up to over 150 degrees in the pile.  This apparently kills pretty much all of the pest eggs,  weed seeds and disease pathogens because I’ve been using it like this for years. If I wanted to heat pasteurize my compost or soil I would do it like this – Solar Heat Pasteurization – or in an oven bag on the grill – not by baking it in the kitchen oven as I have seen recommended.  My wife wouldn’t be pleased if she caught me baking dirt in the oven.

I mix and store potting soil in a clean 30 gallon trash can. I also use steel trash cans to store bird seed, and pet food (I usually leave those in the sack inside the can) They’re not too expensive and they’re fairly effective at keeping out mice and other vermin.  However we had to fasten the lid down with bungee cords last year to keep the raccoons out of the cat food.

Layer in your ingredients.

Layer in equal measures of screened compost, peat moss (or coir), and course vermiculite or perlite, and a bit of organic fertilizer if desired.  You might also want to add some lime to lower the acidity, but I usually don’t.  Shop around for your components – I save a lot of money by buying big bags of vermiculite from a commercial greenhouse instead of little bags from the home improvement center.  If you buy compost instead of making it beware of “compost” that is really just rotted bark mulch – it has almost zero nutrition, dries out quickly, and ties up a lot of nitrogen as it continues to break down.  Bark mulch is bad.

Every few layers (1/4 – 1/3 ways through filling the container) give it a good stir.  If you wait until it’s all full, it’s really quite difficult to mix it all up.

Stir it up several times as you go.

Once you’re finished mixing it all up add about 3 gallons of water.

I add about 2-3 gallons of water, and in a day or two it will all be slightly moist, but not wet.

Adding some water to the container makes the mix less dusty to handle and prepares it to take up water.  Now you’re ready to start some plants.

I’ve used a similar mix for making square foot gardens – basically raised beds.  It’s wonderful to work with, but in hot weather it dries out awfully fast, and I think that a mix which includes some clay or garden soil might actually be better for that application.

You can use many other ingredients for making perfectly usable potting soil – including plain old dirt.  Don’t let a lack of specific soil ingredients hold you back – seeds were coming up just fine long before anyone ever dreamed of buying or selling dirt.

Make up a batch of potting soil now, and you’ll find it easier to get around to the seed starting and potting that you plan to do later.

More information on making organic potting soil – includes many recipes and information on alternative ingredients.

This compost pile is already 155 degrees F after only 3 days! A hot pile like this does a good job of killing weed seeds and disease organisms.

How to do it

• Use your lawn mower to chop up leaves, and then go over them again and use the grass catcher to collect the chopped leaves. If you don’t want to chop up your leaves you certainly don’t have to, but you won’t have to empty the grass catcher nearly as often if you do, and your compost will have a much finer texture.
• Use your lawn mower/grass catcher to collect grass clippings.
• Combine 3 parts leaves with 1 part grass clippings in layers to build your compost pile. I use hoops of wire mesh fencing to contain my compost piles, but it will work fine if you just pile it up without any kind of container or bin. Don’t get too hung up on that 3 to 1 ratio, it’s just a rough guideline. It’s fine to just judge by eye – no need to measure.
• Your pile should heat up within a few days, if not, it is most likely too dry – add water until the pile is moist through and through. If your materials are quite dry sprinkle each layer with water as you build the pile.
• Once the pile has heated up and cooled back down mix the pile using a rotor tiller if you have one, otherwise turn it using a pitch fork or shovel – if you aren’t in any hurry at all then don’t bother turning (mixing) the pile. Given enough time your compost will finish anyway. However turning the pile just one time will greatly speed the process, and improve the results.
• If you are in a hurry, then turn the pile every few days as soon as it starts to cool down – this will make what is often called a fast/hot compost pile, and is very good for killing weed seeds and disease organisms.
• When the pile will no longer heat up after turning it your compost is finished. If you are making slow compost then when it looks well decomposed it’s ready.
• Compost that you make like this is far better than that which is available at home centers. In many cases store bought compost is made primarily out of bark mulch and will harm your soil in the near term by tyeing up most of the soil nitrogen.

My yard has a lot of trees in it so every fall I have to remove leaves, and in the spring I have to mow grass every 5-7 days. Since I have to remove the leaves and mow the lawn anyway I’m already doing most of the work involved in making compost. By putting together my grass clippings and leaves, I make a great balanced compost that finishes quickly, and is a great soil amendment. I don’t use any fancy store-bought compost bins or “compost starters” and I don’t do a lot of work turning the compost (unless I just want to). I also don’t go about collecting compostable materials. Although I probably would if I didn’t have a big yard, because even though I make a pretty large quantity of compost using this method, there are so many uses for it that it’s never too much. For a compost pile to decompose reasonably fast you need to have a mixture of high carbon materials (dry leaves), high nitrogen materials (green grass clippings), air and moisture. The bulk of my compost pile is made up of grass clippings and leaves, but I also throw in other compostables as they become available. If you don’t care how long it takes for your compost to finish then you don’t really have to worry much about what amount and kind of materials you use – just pile ‘em up in an out of the way place and wait for it to decompose.

Compostables include just about any plant materials from your yard or garden, although woody materials like branches or tough pruning debris will take a long time to break down, and probably should be avoided. Other compostable materials include – hair, livestock manure from any herbivorous animals, egg shells, blood meal, cottonseed meal, peanut hulls, rice hulls, crop residue, straw and hay, stable bedding, coffee grounds, newspaper and cardboard (although using things like this will compromise efforts to be “organic”), pine needles – use your imagination. As mentioned before, woody materials take a long time to break down – years. If you do use wood products like sawdust, branches, or bark mulch you should be aware that if you add these materials to your soil before they are fully decomposed they will absorb and tie up a large amount of the nitrogen in your soil and significantly lower the fertility, and they tend to be highly acidic.

Pretty much any organic material will break down into compost if given enough time, but there are a few things you should avoid – meat, flesh, bones or fat of any kind – feces from any animal that eats meat, especially from dogs, cats, or people – Never use these at all because of severe risk of disease. Also avoid; large amounts of watery fruits or vegetables such as tomatoes, oranges, cucumbers, melons, etc – large quantities of prepared food – oil or grease – anything that might draw flies, rodents, or pets. The problem with most of these materials is that they will either become infested with fly larva or take too long to break down, or they will attract varmints, are hazardous to your health or all of the above.

Vegetables (including the watery ones listed above) and non-meat table scraps can be added in small quantities to the middle of a “hot” compost pile without problems.

What do you do with all of this Compost once you make it?

• Work it into your soil at planting time for any plant
• Use as a mulch to suppress weeds while increasing fertility
• Mix with equal parts of peat moss and pearlite or vermiculite for outdoor potting mix.
• The area around a compost pile is a great place to find fishing worms.
• Add as a side dressing (on top of the ground) just as you would use chemical fertilizer for ornamentals.
• Make “Compost Tea” (liquid fertilizer) by soaking a cloth or mesh bag full of compost in a bucket of water.
• Making compost reduces the need for petroleum based and other chemical fertilizers so we don’t have to send as many soldiers to secure our supply of oil.
• Using compost helps to tie up carbon into the soil instead of going back into the atmosphere as CO2, and helps to prevent global warming.
• Compost doesn’t pollute our water supplies or cause nasty algae blooms like chemical fertilizer.
• Food grown using compost and other organic methods tastes better and is better for you.

Addendum – Can You Start a Compost Pile in the Winter – Will it Compost?

It is absolutely OK to start one in the winter – as long as it’s big enough.  I just finished putting one together on Saturday (December 27), yesterday (Jan 1)  it was 150 degrees about 10 inches in – almost hot enough to scald my hand.  You can literally heat a house with a big pile like this.

The outer layers insulate the rest of the pile so that it can heat up, so a big pile does better in cold weather than a small pile.  Minimum size?  2.5 – 3 ft. outside dimension.  If your pile is much smaller it might not heat up in cold weather.

If you don’t have enough material to make a pile that big you can get a bale or two of straw or hay – old or spoiled is fine -  and 2-3 pounds of blood meal (or other high nitrogen organic material) per bale to mix with your other ingredients and it will stretch what you have, and make good compost – a little bit stringy, but still good.

With a small pile you really should turn it as soon as it starts to cool down to keep it’s metabolism up. Make sure you moisten the layers as you build – especially if you use hay or straw.  Once it’s going, you can add additional material as you get it by burying it in the hot compost.

If you don’t want to do all of that, then just save your ingredients until you have enough, or the weather warms up.  Put the greens (high nitrogen) in one pile and the browns  (high fiber/carbon) in another until you are ready to combine them.