Help! My raised bed soil isn't retaining water
Ashley Torbert
3 years ago
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Embothrium
3 years agolast modified: 3 years agoRelated Discussions
What soil do i fill my raised beds with?
Comments (6)Let's consider two issues in turn: what kind of soil, and then how much. The quality of your produce is directly related to the quality of the dirt they grow out of. This makes sense, because plants consist of energy from the sun, oxygen and carbon from the atmosphere, and matter from the soil in which they live. Therefore, it is worth your while to make sure that your beds are full of good dirt. You want to pay attention to a few factors in garden soil, mainly nutrient content and drainage. Once you know what you want, you can buy cheap ingredients and mix them to get what you desire. Base: good ol' dirt A good base for a garden soil mix is the cheap topsoil that you can get at your garden center. Lots of stores sell topsoil for cheap in the spring, like maybe $2 or less for a 40-pound bag. That seems like a lot of dirt, but it's really a negligible amount once you start filling in your bed. Nutrients: compost & peat moss You also want to have a lot of nutrients, so it is a good idea to add in some compost. It's great if you're making it, if not they sell it at garden stores. It's incredibly rich, so it's okay to mix in only a bag or two per raised bed. Peat moss is also a good idea, as it is full of organic matter. It comes in big bags, and is really concentrated so you don't need all that much to have an effect, maybe half a bag for a medium-sized bed. Drainage: sand/vermiculite & peat moss You also need drainage, which refers to the ability of water to seep out of the topsoil. (This is what distinguishes a swamp or marsh from "good" land where you can grow things like tomatoes or corn.) This is aided by little holes in the soil. Since water seeks the lowest level, raised beds inherently have good drainage, but you can make the situation even better. It's a good idea to break up your substrate (the area under your bed) pretty well with a fork or spade before building your bed. You also want to make sure to mix in your added soil with some of your substrate, because an abrupt border can lead to problems with compaction: sometimes roots will never penetrate the substrate if it's not mixed, and drainage will be reduced. It's a good idea to mix some sand into your bed's soil to increase drainage; vermiculite (the white chunks in potting soil) also works, but then it looks too much like potting soil and not enough like a garden for my tastes. The light texture of peat moss can also aid quite a bit in creating better drainage, in addition to the nutrient benefits. That said, it will take a LOT of dirt to fill your raised beds. I built some beds that are 5' wide, 10' long, and 1' high. Each one required a bag of peat moss and 1,600 pounds of topsoil! That's 40 bags of that cheap topsoil, which even at a low price came out to hundreds of dollars for a few beds. I highly recommend against using potting soil or your bill will easily stretch into the thousands of dollars. The way to do it on a budget is to: 1) buy cheap materials 2) mix it yourself 3) use topsoil that is on sale, or maybe even free from a local landfill 4) you can even fill the bottom with straw: a straw bale is pretty cheap and gets you a lot of organic matter. It will biodegrade in a year or two if it's buried at the bottom of your bed, it will increase drainage, it will not hurt your plants, and it's a lot easier to move than dirt. In Scandinavia, they traditionally grow potatoes in straw without even any dirt, and they do fine (plus then they come out totally clean!) 5) don't use potting soil! unless it's old potting soil that you have tossed in your compost pile or something I hope all that helps -- good luck building! Also, it might be a good idea to line the bottom with chicken wire or hardware cloth if you have problems with varmints in your area (so they can't dig up into your bed), or to line the bottom with landscape fabric (to prevent grass etc. from growing up into your bed)...See MoreHELP! Clay Soil in concrete block raised bed on concrete slab
Comments (5)I got your email, Louise - Sorry, I've been away at a bonsai show & visiting friends/family. This is a tough one. As I understand it, you have a concrete block planter constructed atop a concrete slab, with no way for the water to make its way into the sand below the slab. Drilling holes in the block walls won't improve drainage. The only 2 ways to effectively improve drainage would be to make sure there is a 'bridge' between the soil in the planter and the sand below the concrete so the water can percolate through the soil, or to make sure the soil you use is porous enough that it holds little or no perched water. This would mean that your soil particles would have to be large & stable, insofar as their structure is concerned. Even the soil you see me holding above would be inappropriate for your application because that soil depends on the wicking action of the earth (in RBs) to ensure it doesn't remain saturated after rain/watering. It looks great, but if you have high standards it would be a disaster in a container or in your app. I'm thinking that about an 80% fraction of a mix of all purpose sand and all purpose gravel and 10% each of pine bark fines and Michigan (reed/sedge) peat or good compost would probably be the direction I would head. In subsequent years, I think all you'll need to do is mulch with pine bark to keep the soil healthy. If expense isn't a major consideration, you could use Turface MVP as the base ingredient for your soil. Topsoil and fine sand just isn't going to drain w/o help. The alternative would be to remove the old soil and cut a hole in the slab so water can drain from the soil in the planter, but it would have to be a hole of considerable size - preferably at the lowest point on the planter's bottom. If you have pictures, it's possible that something else might be devised that will allow the water to move out of the soil via some sort of passive wicking mechanism that we/you could devise, but I'd have to see the application in order to envision the possibilities. There might be a way to employ a false bottom by placing FRP panel on top of cement blocks that are resting on the bottom & building it like a self-watering container in reverse - where you employ a wicking column of soil to REMOVE water instead of supplying it, but I don't know how far you want to chase the issue? ;-) AL...See MoreRaised Beds Retaining Water?
Comments (12)Alright! This is great and we're feeling pretty hopeful about things at this point. Here's a brief rundown of what we're looking at, in case any of you are curious: - 3 tomato plants of different varieties, 2 of which look excellently strong, and one of which, a cherry tomato plant, has some yellowing leaves at the bottom, but a teeny tomato growing, which we are very excited about - our first fruit! Will keep an eye on the yellowing, but think that was probably a result of the overwatering. - 2 pepper plants, a jalapeno and a habanero - the jalapeno is strong, but the habanero was fading fast. We transplanted the habanero into a pot with some "organic potting soil," and moved it to a slightly shadier area near our very tiny garden - hopefully the nutrients in the potting soil will bring it back, and we'll keep it from the hot-hot sun for a day or so to see how that goes (we're having 85+ degree days here). Will water it in a day or so, because the peat pot it was still in when we transplanted was still very moist from the "overwatering" - cilantro - which is gloriously thriving at the back and shadier end of the garden. Wow, this thing has taken off, and we are thrilled. We love cilantro, and it's so nice to have something so obviously working! - basil - see above notes for cilantro. Woot! When we removed our wavering habanero, the cardboard beneath was indeed very saturated, and produced no resistance when punctured. So thankfully we no longer feel the need to remove it and disturb the whole system. We've driven holes through in several places to help with drainage. These forums are very encouraging, and again, we're grateful for these suggestions!...See MoreSoil not retaining water?
Comments (9)In decades of gardening, I've never had a circumstance where peat and/or vermiculite did more good than harm (not including containers). The situation will eventually work itself out, but my policy is to never add anything that mother nature wouldn't. "Good soil" just takes time, kudos to you for getting started! Assuming the raised beds are directly on the ground, the plants will soon get their roots down into the - clay? - and be better able to withstand dry conditions more easily then. I would mulch too. A finely shredded wood, so it helps add tilth to your soil by decomposing quickly. Growing veggies is not the easiest thing to do, you'll have lots of learning experiences. For example, even if it goes right, it can go wrong. About 12 years ago my daughter planted watermelon seeds and I didn't pay any attention to the package. One of the vines grew a melon but it stopped growing long before I thought it should. After about a month of waiting for it to get bigger, it never did so I cut it off and sliced it open. I was so disappointed to see that it was orange inside and hadn't even made any seeds yet. I thought it was poisoned from the neighbors lawn service (heavy rains would cause a flow from their yard into ours) and threw it on the compost pile. The next spring I was looking at veg seeds and saw a package of little round ORANGE seedless melons. Well duh, I didn't know there was such a thing. I probably threw out the best edible thing we grew that whole year! I think the curse of the scorned melon was finally lifted last year. Mother nature let 2 little melons ripen enough for us to eat but not get torn up by squirrels. Good luck, keep trying & have fun!...See Moredaninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
3 years agolast modified: 3 years agoLoneJack Zn 6a, KC
3 years agoarmoured
3 years agoEmbothrium
3 years agogardengal48 (PNW Z8/9)
3 years agoEmbothrium
3 years agolast modified: 3 years agogardengal48 (PNW Z8/9)
3 years agolast modified: 3 years agoarmoured
3 years agolast modified: 3 years agoharry757
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3 years ago
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