Love Dirt: Healthy Soil, Healthy Future by Dr. John Paul

How fortunate we were to have soil scientist, Dr. John Paul, speaking to our garden group about worms and soils! His main business is designing soil systems for Transform Compost Systems and he has grown worms and produced done worm casting for more than 20 years!

John started off by wowing us with the fact that there are 50 billion microbes in a gram of soil! What is soil…95% or more is just bits of rock. Organic matter makes up only 1% to 5%. The devastating fact is that we have actually lost 50% of our organic matter worldwide.

John explained that soil organic matter improves soil physical properties. Increased soil matter increases soil water holding capacity, which is important in sandy soils. It improves drainage in clay soils, making them more productive. It increases soils ability to hold nutrients and the ability to resist changes in toxicity in acidic soils. Soil organic matter improves soil biological properties. Soil microbes, root growth, and nutrient cycling all improve.

We can increase soil organic matter by adding compost. Compost is NOT soil! Put it on potted plants; use it as mulch in the garden; add it to the soil of your lawn. Compost is dark brown, crumbly, and has an appealing earthy smell. A well-made compost is free of potential pathogens and can increase disease resistance.

Compost can make up to 10-25% of your potted plant mix but be sure to read and follow directions or you can burn your plants. When used as a mulch in the garden, mature compost provides organic matter with beneficial microbes, decreases water loss, and inhibits weed seed germination. It is better than mulch as it provides nutrients. One caution is to be sure that compost for vegetables is free of potential pathogens. ”Barn yard” compost doesn’t get high enough to kill pathogens. Compost on lawns is a great time saver as you no longer need to aerate, dethatch, control moss, or add extra fertilizer. Aeration is only useful when soil is dry or the soil just smears. (Note keep your clippings on your lawn as well!) Well decomposed mushroom manure is good for lawns. Compost is also helpful for erosion control on hillsides.

There are different methods of “Backyard Composting” but just leaving the material sit doesn’t mean it is composting well. Actively composting means adding air, so don’t use tarps as a cover. Products normally used as housewrap, available at the hardware store, such as Tyvek or Typar, allow the matter to breathe. The compost pile will have to be turned as well. Pests such as rats and bears are a consideration. Not adding meat helps minimize the attraction for rats but it is important to note that rats and mice love the warmth in a compost pile. Grass clippings result in higher temperatures, and if hot enough, the bears won’t want to get their noses burnt.

Another method of backyard composting is by using a special container. Containers, such as the “Jora composter”, are insulated and can bring the heat up to 60 to 70 degrees Celsius. You can turn a handle to rotate them.

Another method is the “compost barrel”. It is a closed system, so discourages pests. It is sometimes recommended to add microbial organisms, but if you are creating the right microbes in your compost then John maintains that this additive is unnecessary. If your conditions aren’t ideal, then compostable materials inoculants can be added to speed up the process.

Worm composting is another type of system. With the right conditions John told us that the number of worms can double in 3 weeks. He suggested www.cityfarmer.org as a great resource. When worms slither, they produce a slime which, in worm castings, has beneficial nutrients and hormones which act as a growth stimulant, particularly for roots. John was asked about harvesting the worm compost without losing your worms. Worms are typically top feeders, so the bottom doesn’t have as many. You can separate out the worms using screen, or by using light to get them to go down. One of our members mentioned that she puts in mango skin, cantaloupe skin, or pineapple and then can scoop out handfuls of worms.

We learned, (to my personal dismay!), that the liquid that comes out of a worm composter or a compost pile really isn’t “Compost Tea”. Proper Compost Tea has a recipe with additives (like molasses!) and is aerated for 24 hours. When sprayed on leaves, it creates a biofilm which aids in disease resistance.

The question of worms in outdoor composts was mentioned. John said that worms can’t take temperatures above 28 to 30 degrees Celsius so grass clippings get too hot. In general, worms need a moisture content of at least 70% in the compost.

If you were contemplating buying a “Kitchen Composter”, John explained that these don’t actually “compost”. They dry and grind food waste, which is useful, but is not real composting. He showed us comparisons of “real compost” and “kitchen compost” out in the garden. Once the rain rehydrates it, it goes moldy!

The topic of European chafer beetles came up of course! If you just add nematodes to poor soil in the lawn, you will just have to add them again. If you have good compost the nematodes have a much better chance of surviving. A well-made compost will have beneficial nematodes already in it! Beneficial nematodes need good organic matter in soil to thrive.

John finished his talk by encouraging us to think about the benefit of increasing the diversity organisms in our soil. Organic matter enriches the garden and makes for healthy soil. If you are not adding it now, then get to it!

Thank you, John, for passing along some very important information!
It was so worthwhile to get the facts from a real “Soil Scientist”!

RELATED LINKS