I have a strip of old asphalt that is an eyesore. It foundation wall faces SSE and gets noon to evening sun. The deck shades most morning sun. The outside posts are on the property line. There is a hose bib that needs access behind the old stairs so I would need a window well if I go against foundation.

Here is a pic.



I have already started stocking up on material. This is what I have so far

Plenty of straw bales
Plenty of wood shavings/sawdust
Plenty of cardboard

There is an old fallen Cotton wood across the road that is easy to crumble.
I can get more forest compost and soil along the river.
I will have huge amounts of grass clippings throughout summer.
I have 2-3 ft of rich river bottom topsoil and can dig up as much as needed. The ph is above 8.

The river makes it a natural wicking bed so I only have to water occasionally in late summer. The well water has a ph of 8.2-8.4 and has high nitrates. The river water is about the same as well water. The worms are abundant so everything grows super tall and fast. They are even in the gravel driveway so I think they would move into a bed above asphalt. I also have compost with many worms but not enough to fill rased bed. The problem seems to be lockout of K and micros when veggies peak in my other gardens. I want this bed to have a lower ph for peppers and strawberries.

My idea was to use the straw bales to make the perimeter of a raised bed. Line the asphalt with cardboard and add a layer of rotten Cottonwood. Fill in the gaps/layer with topsoil or forest debris. I'm not sure what to add after that. Everything would be free. I can get leaf compost or compost/topsoil mix from a reliable organic source for 30/yd.


Here is the back yard bee and herb garden. It was all gravel at one time. The house used to be the general store for the summer river cottages so everything was gravel and asphalt. It grew weeds more than grass. I put down 6 to 8 inches of grass clippings and 10 in of straw. I am in the process of adding 6 in of saw dust now and have started around the TB Hive.



Let me know if I'm on the right track.

hau, Jim. I like your plan of attack, the cardboard laid on top of the asphalt will give a short term barrier but from the looks of it, it has been there for a long time and so probably is pretty stable (leached out) already. I would use those steps for some straw bales for growing strawberries, you can plant them on the tops and the sides, they should grow pretty well there as well as give you room for other plantings, that way you don't have to rip out that concrete and dispose of it. You can do a lasagna layered composting inside the bales or a jumble method. The river soil will be good for the layer method or the jumble method. That will just leave the pH adjustment, which can be started when your putting in the materials. Way to go!

Bryant RedHawk wrote:hau, Jim. I like your plan of attack, the cardboard laid on top of the asphalt will give a short term barrier but from the looks of it, it has been there for a long time and so probably is pretty stable (leached out) already. I would use those steps for some straw bales for growing strawberries, you can plant them on the tops and the sides, they should grow pretty well there as well as give you room for other plantings, that way you don't have to rip out that concrete and dispose of it. You can do a lasagna layered composting inside the bales or a jumble method. The river soil will be good for the layer method or the jumble method. That will just leave the pH adjustment, which can be started when your putting in the materials. Way to go!

The stairs used to be where the house sat. I jacked the whole house up 7 ft to get 2 ft above 100 year flood. I have fought ph for 5-6 years with compost, pine needles and leaves. I read here about not fighting it and just let the microbes do their thing. Keep adding compost and don't til. I am mixing peat in with the veggie hole this year to see if that will help. I don't want to get on a sulfer regiment.

Back to the new raised bed. I just laid some bales out for a prelimainary design. I have it so that flood water can drain around the back of the house. The mix can go up over the stairs for strawberries. The neighbors dog loves the straw and found a new perch.


What about the rotten Cottonwood? Are the bales to shallow with the asphalt bottom for them to be effective? I want to get as much low ph organic in there as possible and keep the native soil to a minimum.

Here is the Cottonwood. Someone cut out the good firewood and left a mess.


Plenty of river debris pile up here.



I also found some 1/2 rotton hay bales for some more greens.

Call it a day. Hay next?

Howdy Jim, Here is an older thread about asphalt.

http://www.permies.com/t/13571/organic/Safety-planting-asphalt

And a video about it.



More ideas.

Jim, peatmoss is a good acidifier so that is a good amendment to get that pH lower. I would suggest getting some gypsum to add as a buffer, it will also keep your bed nice and friable. I like the way you are building the bale bed.

Removal of asphalt is usually the best, but I personally prefer to use a bar or hammer drill to poke lots of holes instead of creating more landfill material. Introducing fungi such as oyster mushroom spawn will begin the breakdown process. Since you are putting all that wonderful cottonwood in there, and I'm sure it already has decomposing fungi growing in it, you are well on the road to making all of the asphalt that can, go away by fungal feeding.

Miles, thanks for the vids.

Bryant, there is a foot of gravel under the asphalt. It would be a major pain to remove. The Cottonwood already has mushrooms growing all over. A lot of the pieces are like sponges. You can squeeze the water out. I am hoping it will hold moisture through the afternoon sun.

The native soil is fairly sandy/loamy. My other garden is easy to dig and just the right amount of clay to hold moisture. I mixed in peat to plant my onions and really like the feel. I think 2 in of peat mixed with 2 in of top layer will help with ph. Tomatoes, beans and cucs grow 10 to 15 ft every year. They shut down on fruit production. The lower leaves turn brown and fall off but the tips keep growing. Then septoria, PM and late blight take over. I am hoping the lower ph on top with help with lockout and the tap roots can seek moisture in the lower dirt. I also plan to mulch with sawdust/wood turnings.

Yes, I would not bother trying to remove that much asphalt either. For a situation like that, if and only if drainage were a problem would I even bother trying to break it up some. The bales you are using as a border will give you plenty of depth over time. Once you have the bed built, yearly amendments will create some great soil for vegetables. The wood, along with the fungi it already contains will hold lots of water and once you have it covered it will hold that water longer allowing your plants to thrive. I would do some spot testing for mineral content, and major nutrient content, simply so you have a roadmap to follow for additions as you go along. There are kits you can purchase for this or use your extension service to do the tests, the alternative is to observe your plants and use what their leaves and fruits tell you is going on with nutritional value of the soil as your guide to improvements. As I've said, you are on a good path already.

Bryant RedHawk wrote:Yes, I would not bother trying to remove that much asphalt either. For a situation like that, if and only if drainage were a problem would I even bother trying to break it up some. The bales you are using as a border will give you plenty of depth over time. Once you have the bed built, yearly amendments will create some great soil for vegetables. The wood, along with the fungi it already contains will hold lots of water and once you have it covered it will hold that water longer allowing your plants to thrive. I would do some spot testing for mineral content, and major nutrient content, simply so you have a roadmap to follow for additions as you go along. There are kits you can purchase for this or use your extension service to do the tests, the alternative is to observe your plants and use what their leaves and fruits tell you is going on with nutritional value of the soil as your guide to improvements. As I've said, you are on a good path already.

Thanks for your help. I have a soil test kit but I've only used it for ph. I can somewhat read leaves. I just can't grow peppers and strawberries here. Drainage is not an issue since I'm used to flooding and have designed around it. The whole bed might float away next spring. The flooding usually happens with a warm front or ice breakup Dec-Feb. It has not flooded past March in 10 years so I hope it will be rooted down by winter.

I'm still unsure what to add for the next layer. The rotten hay and partially composted leaves seem like they will sink in the voids best.

I would go with a mix of the two, the combination will fill voids, the mix will also get the benefit of the fungi growth, giving you a deeper spread of mychordial organisms which is a good thing.