Pete Bottomley is a man who knows soil and compost. With 25 years in the "green Industry," Pete’s experience includes selling for Monrovia, one of the Nation’s most respected growers, founding a garden center employee training company, and consulting with garden centers about marketing, merchandising and training. He is currently a partner in Coast of Maine, an organic gardening products company and is the owner of Casco Bay Safelawns, in Scarborough, ME. He also represents Bradfield Organics, makers of natural fertilizers. He lives in Cape Elizabeth, Maine with his wife and three children.
I spoke to Pete at the Coast of Maine offices in Portland, Maine.
Let’s talk about compost.In the best case, you have a hot compost. To kill weed seeds and pathogens you want it hot. Believe it or not, compost will get up to 150°F. That’s about as hot as it gets and then something will run out: food or air or water, and then the temperature will start to drop. When you’re making good compost, you’re carefully monitoring it all the time so that you know everything that’s happening.
At Coast of Maine, once we get the compost to the point where it doesn’t heat up any more, which takes about three weeks, we then cure it for a good nine months.
Can people do a hot compost at home?Having a hot compost pile at home is pretty hard. It’s kind of like raising a puppy – it needs lots of attention. You have to think about it and tend to it all the time. Even if you buy one of those tumblers, if you don’t tumble it or make sure it has enough moisture you’re going to have a really crummy compost product in there. The first thing that happens when it dries out in there is that it gets full of white fungus which basically eats all the good stuff.
What’s cold compost?The easiest way to make cold compost would be to dig a hole in the ground, put a cone on it and dump your food scraps, grass clippings and leaves in there. You never turn it, you never do anything and then every year, or so, you take the cone off and you’ve got compost in there. It just happens. Worms get up in there and they do the work.
I always wondered if it’s counterproductive to put non-organic plants into your organic compost.Put them in. Compost is kind of neat because it will undo a lot of evils. It’s one of the best mitigators there is. Have you ever seen when they take up the tanks at a gas station? They take the soil away that has been contaminated and compost it. They mix it in with active compost and eventually bacteria will grow to eat the bad stuff.
Let’s talk about fertilizer.What you want to do in a container is to foster an ecosystem that is alive and vibrant. One of the best ways to do that is to provide the right kinds of food. When you’re feeding an animal or a person, high quality nutrition makes all the difference. So when you’re feeding the soil to grow plants you want to have high quality nutrition. People have used manure for generations and it works, but manure has been processed by an animal, and has had a lot of the nutrients taken out of it. Other really good sources of food for your plants are alfalfa and corn gluten, which are ingredients that make great fertilizer.
Is there a safety issue with chemical fertilizer when growing vegetables?Using a synthetic soluble fertilizer in a container garden isn’t going to hurt anybody, however a tomato grown without a full palette of nutrients is going to taste bland. A tomato that is grown in soil that is alive is going to taste fantastic. There’s a huge difference.
Would you ever recommend top dressing containers with compost?Absolutely. It’s a great idea. You can use composted manure, or the Coast of Maine Lobster Compost. If you get your compost from a local source, make sure that they’ve had high temperatures in their compost. You don’t want a weed explosion.
Any advice on using potting soil?
Once you have plants in it, don’t let your potting soil completely dry out. If you let that happen, especially if it has a lot of peat, you can get a hard layer on top, or the whole thing can form a solid clump. Then when you water it, the water doesn’t sink in, it just goes around the edges.
Is there anything you can do to help potting soil to retain water? What about water retaining crystals?
I don’t like those! They’re made out of polyacrylamide, and there’s research showing that the compound can break down to release acrylamide, which is a neurotoxin. No one talks about that now. They do tell you to wear gloves though, when you use products that have that stuff in it. We shouldn’t have to put chemicals in our soil to help hold water, compost does the job well, naturally.
Let’s talk a little about the difference between using a product like Miracle-Gro and organics.
First of all, people have a misconception that going organic is more expensive. Well, it’s not -- it’s actually cheaper.
A liquid like Miracle-Gro or Shultz liquid plant food is made of nitrogen, phosphorus and potassium in a soluble form, which is a form that plants can take up right away. But it’s also a salt, so if you have bacteria, fungi and protozoans in the soil, the water gets sucked out of them and they die. These kinds of fertilizers make plants grow, but the soil life gets killed in the process.
Also, you have to put this stuff into the soil every couple of weeks, which is expensive and time consuming. With an organic, you can mix a granular fertilizer in at the beginning of the year and you’re done. If you live in a place with a long growing season and have really vigorous plants, then you might have to hit them in August with a fish fertilizer, or top dress with a granular organic, but that’s it.
Organics are less expensive, less time consuming. They feel better, look better, and your food will taste better.