February 14, 2011 Garden Math: How many Bags Do We Need?
http://nowataoklahoma.wordpress.com/page/6/It happens all the time. We purchase bags of soil, additives, or soil amendments for our flower or vegetable beds, bring them home, unload the car, lug the bags into the garden, pour and spread them on the beds. And then, lo and behold, we discover that the quantity we bought is not enough. Now the process must begin again.
Life is too short and our discretionary time too valuable to repeat any action unnecessarily. It would be more efficient if we had a guide to help us calculate, in advance, how many bags of garden product we need. One prominent nursery in Montreal, Jardins Jasmin, has posted such a guide online, but since their site is in French, I have translated their data as follows: - To cover a 10 feet by 10 feet area with 3 inches of garden product, based on standardized, retail-sized packaging, one will need 9 bags of top soil, or 9 bags of mulch or 23 bags of black earth. To lay grass over that same area, 10 rolls of sod are required.
This information has also been visualized by Greg Draiss who blogs at The Real Dirt on Gardening. In one of his blogs, he posted a YouTube video tutorial explaining how to calculate the amount of bags of soil, stone, bark, compost or mulch the gardener needs in order to spread a layer of garden product 3 inches deep This is a most useful guide for DIY gardeners. Hopefully, it will help to reduce the time allocated to buying and unloading. Click here to watch the video.
A measure of 3 inches is used because that is the minimum amount of mulch required to keep garden beds reasonably weed free. Spreading generous layers of any product is a far more efficient use of time and labor than spreading thin frugal layers. Not applying enough results in re applying again, sometimes immediately and often later in the season. Life is too short and too busy. Do it properly the first time round.
Reader Comments (5)
I can't tell you how many trips we make just guessing at how many bags of mulch, soil, etc. Thanks for the info.
Eileen
Hi, Allan, Thanks for the calculations.
I'm curious about your perspective on bagged manure. Regardless whether it's sheep or cattle manure, I have noticed that the bags from most garden centres these days seem to be cut with sand -- which, of course, adds to the stated weight. Now, for a sandy garden like mine, that's like bringing coals to Newcastle. And I've put many, many bags of manure into my garden.
This year, I'm strongly considering going halves with a neighbour and ordering a truckload of loose composted manure... preferably if I can have a look at it first. O
Your opinions on this?
It's also not a big deal to calculate it out by hand. Times width, length, height (3 inches), (convert all numbers to same unit), and there's the volume you need.
Helen,
I am not a fan of bagged manure. I have not been satisfied with the results that it has given me. You are correct to consider trucked composted manure but I fear that even half a load might be too much for your garden. The aroma certainly won’t be endearing to the neighbors. I would get a quote on it and then do a price comparison between the cost of half a load and the cost of using other bagged products such as those mentioned below.
Here are some ideas to consider
1] The city of Toronto distributes free compost to its residents each spring. I cannot give you a valid scientific explanation why but I prefer that sort of “vegetation and kitchen scrap” compost to manure.
2] I recommend adding bagged “black earth’ [usually sold at big box nurseries here in Quebec and not available everywhere in Ontario] to the soil to contribute to the balancing of the sandy soil
3] Fafard brand Sea Compost is a rich additive for sandy soil, but it is a bit pricey.
4] In the fall, instead of bagging raked leaves, I would run a mower through a leaf pile, sprinkle the resulting mulch over the garden beds, water down thoroughly and let nature do its job to enrich the soil.
The beauty of plant based compost is that it has a higher humidity content than manure that might allow you to postpone amending the soil again for another three years.
And then again, you might have to experiment to see what works best in your area.
Hope this helps.
Hi, Allan,
Thanks for your thoughtful response. I've been raking my leaves onto my garden for years (as well as stealing bags of leaves left for the garbage), and one of the best investments I ever made was a leaf shredder a couple of years ago, which really speeds up the composting process. All the shredded leaves go onto the garden.
You're right that the City has a composting program and does give away compost. However, you're limited to the amount you can carry, which might be a couple of garbage cans full (Though I have a neighbour with a pickup truck. Hmmm.).
If not pure manure, I might look into some of the trucked soil mixes that are available, some of them include a good chunk of manure. I'll post on my findings and will let you know.
One of the soil miracles I've learned about is having it blown in (!) like one of the machines you'd use to spread blown-in insulation. However, that would work only with a brand new bed -- it would bury my existing garden. But who knows, one day I might have a new garden...