I think I added too much peat moss to my soil...

[kbrown1337]

I have pretty tough clay soil, and I read that peat moss would help. My garden is a raised bed, 48 square feet, about 1 foot deep.

I mixed 14 cubic feet of compost, 18 cubic feet of topsoil that I bought, and 3 cubic feet of peat moss, and the rest was the hard clay that I broke up while mixing all of this stuff together. The result was a pretty airy, rich, dark soil that I thought looked pretty good. But once I tried watering it, all the water just puddles on the top and turns the top of my soil into this thick, muddy sludge

And when I dig down into my soil, it comes up as big chunks. It looked nothing like this when I was mixing it all up.

I've been reading that peat moss can repel water, so I think I may have made a mistake. I'm wondering if there's anything I can do to fix this, since my entire bed is now filled with this mixture :/

[Lindsaylew82]

I have pretty much always had to premoisten peat moss prior to removing it from the bag and mixing it. And warm or hot water works better IMO that cold.

Since you already mixed, I would get your mister out and mist the top, turn it over, must the top, and then wait. Go do laundry or something that takes time.
You could flood the entire bed, and I mean FLOOD IT, and then come back the next day, turn it and food it again. If it's clumping terribly, I would add some roughage. Pine needles or straw. And then do the same thing. Spray. Wait. Turn. Repeat.

[GardenThrive]

It sounds like that soil mix is retaining too much water. In my raised beds I use equal parts compost, peat moss, and vermiculite. The vermiculite breaks up the soil structure keeping it from getting too compacted and provides great drainage. 3 cubic feet of peat moss is not much at all for that size raised bed. I would have 5 times that much for a 48 cubic foot bed. Most peat moss comes in compressed bales that you really have to break apart and shred before mixing it into the soil. Maybe that's why you're getting the chunks when you dig down? When I'm mixing my soil I do a thin layer (few inches) at a time and wet down each layer thoroughly before doing another. Peat moss will repel water at first and this helps the soil absorb water evenly. I would think if you added some vermiculite, perilite, or sand it would greatly improve the drainage of your soil.

[kbrown1337]

I have pretty much always had to premoisten peat moss prior to removing it from the bag and mixing it. And warm or hot water works better IMO that cold.

Since you already mixed, I would get your mister out and mist the top, turn it over, must the top, and then wait. Go do laundry or something that takes time.
You could flood the entire bed, and I mean FLOOD IT, and then come back the next day, turn it and food it again. If it's clumping terribly, I would add some roughage. Pine needles or straw. And then do the same thing. Spray. Wait. Turn. Repeat.

I had no idea that it should be pre-moistened! I just took the dry peat and mixed it right in. Would flooding it be better than misting?

[kbrown1337]

It sounds like that soil mix is retaining too much water. In my raised beds I use equal parts compost, peat moss, and vermiculite. The vermiculite breaks up the soil structure keeping it from getting too compacted and provides great drainage. 3 cubic feet of peat moss is not much at all for that size raised bed. I would have 5 times that much for a 48 cubic foot bed. Most peat moss comes in compressed bales that you really have to break apart and shred before mixing it into the soil. Maybe that's why you're getting the chunks when you dig down? When I'm mixing my soil I do a thin layer (few inches) at a time and wet down each layer thoroughly before doing another. Peat moss will repel water at first and this helps the soil absorb water evenly. I would think if you added some vermiculite, perilite, or sand it would greatly improve the drainage of your soil.

Thank you for the advice! I didn't add any water when I was mixing everything together, so you're probably right. How much vermiculite would you recommend adding? And should I mix it into just to top few inches or into the whole bed?

[Lindsaylew82]

The bigger the water drop, it'll just roll right off. I would mist and turn. The mist sticks to it better. Flooding is faster, but heavier. If you could somehow get hot water out there, that would work even faster. If it's clumping, I would add something chunky. I personally don't like to add synthetic chunkies to my soil, but I just have a garden out in the yard. And I have several ponds that my land runs off to. I don't like sand because root nematodes like sand. Sand does help with the clay though! Whatever chunkifier you decide to add, do it before you moisten.

[kbrown1337]

The bigger the water drop, it'll just roll right off. I would mist and turn. The mist sticks to it better. Flooding is faster, but heavier. If you could somehow get hot water out there, that would work even faster. If it's clumping, I would add something chunky. I personally don't like to add synthetic chunkies to my soil, but I just have a garden out in the yard. And I have several ponds that my land runs off to. I don't like sand because root nematodes like sand. Sand does help with the clay though! Whatever chunkifier you decide to add, do it before you moisten.

What would be the best thing to add? It seems like no matter how much I break the clay up, it eventually bonds back together.

[applestar]

Try watering if needed, then covering the bed with soaked cardboard, then just for this period, plastic tarp -- like painters tarp. Let it sit like that for a day or two. Then lift up the cardboard and knead the mix -- you want it to be like pie dough before adding water -- crumbly but holds together when held.

Add more water if needed. Take off the plastic if too wet, but leave on the cardboard held down with bricks or something. Covering with grass clippings is good too. If you have earthworms in your garden, then they will gather and have a party.

[GardenThrive]

For that size bed I would add at least 10 cubic feet of vermiculite. I buy it in the large 4 cu. ft bags at my local nursery.

[imafan26]

Peat moss is repellent until it get wet. It is better to pre moisten it before adding it, but it will wet if you water it enough. Turning will help but don't do that when it is really wet. I think it is not so much of a problem with peat moss but that you have lots of compost and peat moss and not a lot of drainage material. 3 cu ft of compost is miniscule compared to 14 cu ft of compost. Coarse sand or cinder will help to lighten it up. You could use perlite or vermiculite but with that volume you would have to add about 5- 4 cu ft bags. Mel's ratio 1 part soil 1 part compost 1 part drainage material

[applestar]

Wow, I didn't realize it's so popular to add stuff like perlite and vermiculite out of the bag to in-ground raised bed. I use them for container mix sometimes, but only if I need to have a lighter -- as in weight -- mix. I do recycle old potting mix into compost and that eventually finds way into raised bed and other in-ground garden beds, and sometimes I put old potting mix directly in the ground.

but... Perlite floats away and vermiculite compresses into mica flakes.

I'm with Lindsay and imafan and would go with sand or larger chunky sand -- paver sand is how I think of them. I sometimes add gravel, composted root mulch.... Mostly chunky bits from my own compost pile.

Was the clay crumbly when you mixed in all those other ingredients? Did you crumble them up together evenly eith your hands or did you turn with garden fork or shovel, hoe, rake, etc.. And assume they were mixed? is that why you are still finding whole chunks of clay?

[Allyn]

Wow, I didn't realize it's so popular to add stuff like perlite and vermiculite out of the bag to in-ground raised bed. .....

I know that Mel's Mix from Square-Foot Gardening is 1/3 peat moss, 1/3 coarse vermiculite and 1/3 five-part compost (meaning a mixture of five different composts). It's a popular planting mix that I've used even though I don't exactly square-foot garden.

[imafan26]

I made the mistake of not adding the right amount of perlite to the garden. I was trying to improve the drainage and I had a lot of perlite left from pots and cutting pots. I put almost pure perlite and mixed it with the clay soil without the compost and got cement. The clay just glued the perlite together and it drained well but nothing really grew well, so the ratio is important. Coarse sand is also called builders sand and you will find it in bags or in bulk where you get construction materials. They use it to make cement. It is heavier than perlite or vermiculite and does not hold water much. Cinder is also heavy but it is easy to get here, it just is not the best choice if you are growing root crops like carrots that like a finer soil.