With spring on its way, it is time for urban gardeners to get the raised beds in shape. I recently attended a public meeting put on by the Mayor’s office and the Boston Redevelopment Authority (BRA) on urban agriculture, and one of the main topics/concerns was soil safety. The view expressed at this meeting was that it is better to assume that there is lead in your soil in an urban setting because that is most likely the case. So, this year we set out to make sure our garden is free from unsafe contaminants. I will share with you what we have done to get our garden set up for this growing season.
We decided to have our soil professionally tested. After some research we found that it can be easily done through University of Massachusetts Amherst. (Here is the website http://www.umass.edu/soiltest/). We took samples of the beds and the earth they were on top of and sent them off to to be tested.
Thankfully the tests came back with a safe results for the raised beds. (We had used only our compost and topsoil purchased for gardening at the local gardening supply store). The earth outside of the beds however tested with very high levels of lead, an unsafe (for growing food you want to eat, as well as do not inhale dust) amount of lead.
Here is a document on how to interpret your test results.
We decided to have our soil professionally tested. After some research we found that it can be easily done through University of Massachusetts Amherst. (Here is the website http://www.umass.edu/soiltest/). We took samples of the beds and the earth they were on top of and sent them off to to be tested.
Thankfully the tests came back with a safe results for the raised beds. (We had used only our compost and topsoil purchased for gardening at the local gardening supply store). The earth outside of the beds however tested with very high levels of lead, an unsafe (for growing food you want to eat, as well as do not inhale dust) amount of lead.
Here is a document on how to interpret your test results.
| soil_testing_interpretation.pdf |
Wanting to keep the raised bed soil in good shape, we decided to put a protective liner between the bed soil and the earth below to stop the roots going into the contaminated soil, and to diminish the mixing of the two soils. We will also look into growing some ground cover plants to keep the rest of the soil firmly down, and to stop the wind from spreading the dust.
First step was the raised beds.
We ordered landscaping fabric from FarmTek (www.farmtek.com) to put a liner in between the beds and garden soil. Knowing that we'll loose some soil in the process of moving everything out and back, we also purchased 10 additional bags of cheap, but clean, top soil. For the fertilizer, we opted to go the natural way: 6 bags of composted manure and a small bag of bone meal.
We set out a tarp to transfer the soil from the beds to. (If you use this method be sure to use an old tarp that you will not mind putting a few holes in with all the shoveling. It’s hard to avoid, especially if you have enlisted the help of an enthusiastic seven year old.) We removed the topsoil from the bed leaving an inch or two of it behind as a buffer and then put the landscaping fabric down in the beds pinning it in the corners with ground staples. If you are mixing in compost with your topsoil I would recommend doing so in a wheel barrel or on a tarp before adding it to the beds if you are concerned about disturbing the liner you put in place.
We ordered landscaping fabric from FarmTek (www.farmtek.com) to put a liner in between the beds and garden soil. Knowing that we'll loose some soil in the process of moving everything out and back, we also purchased 10 additional bags of cheap, but clean, top soil. For the fertilizer, we opted to go the natural way: 6 bags of composted manure and a small bag of bone meal.
We set out a tarp to transfer the soil from the beds to. (If you use this method be sure to use an old tarp that you will not mind putting a few holes in with all the shoveling. It’s hard to avoid, especially if you have enlisted the help of an enthusiastic seven year old.) We removed the topsoil from the bed leaving an inch or two of it behind as a buffer and then put the landscaping fabric down in the beds pinning it in the corners with ground staples. If you are mixing in compost with your topsoil I would recommend doing so in a wheel barrel or on a tarp before adding it to the beds if you are concerned about disturbing the liner you put in place.
Separating out the good stuff from the compost.
We placed a couple of cinder blocks on the tarp and stretched a length of wire mesh over the top of them to make a compost sifter. It worked great for separating the old roots out of the soil too. We also set up an earth worm sanctuary (flower pot with some soil in it) to be sure that our hard working friends made it back into the beds unscathed. (This is a perfect job for an enthusiastic seven year old!) After the topsoil and composted manure were mixed we returned it to the beds. The bone meal was mixed in at the end, into the top inch of the soil. We added this as per recommendation from the soil test, which also indicated slight lack of phosphorus in our soil.
This whole process took us the greater part of the day but was well worth it for the piece of mind. We already replanted winter garlic and asparagus that were in there before, and after only two days in the new soil they are looking better then before. All this moving and shaking did not hurt them a bit, it helped loosen the soil and in the process got rid of some nasty grubs. (Our backyard helpers: robins were very happy with the meal provided in the process!) We also seeded the first crop of the season: spinach, arugula, lettuces, beets, kale, dill and mustard greens. All those are hardy plants that actually like cooler weather, and we should have some fresh greens to put on the table soon!
-Matt
This whole process took us the greater part of the day but was well worth it for the piece of mind. We already replanted winter garlic and asparagus that were in there before, and after only two days in the new soil they are looking better then before. All this moving and shaking did not hurt them a bit, it helped loosen the soil and in the process got rid of some nasty grubs. (Our backyard helpers: robins were very happy with the meal provided in the process!) We also seeded the first crop of the season: spinach, arugula, lettuces, beets, kale, dill and mustard greens. All those are hardy plants that actually like cooler weather, and we should have some fresh greens to put on the table soon!
-Matt
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