Williams1
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Different soils

Hi, just always wondered what's the difference between garden soil, potting soil, top soil, mulch, raised bed potting mix?

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rainbowgardener
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Re: Different soils

"garden soil, potting soil, top soil, mulch, raised bed potting mix?"

Garden soil is dirt. It is what is there in your yard before you do anything to it. "Garden soil" is sometimes sold in bags, but watch out for it. It can be anything including dirt they dug out to put a building in. It will usually say on it not for use in flower pots and may say something like not for use in flower beds, intended for fill only.

Top soil is supposed to be just the top few inches of the soil. It should be higher quality, with more organic content, less clay and rock.

Potting soil (which is really a misnomer, because usually there is no soil in it; I call it potting mix) is a mixture of things usually including compost and/or composted manure, peat moss, perlite. It is much lighter and fluffier than soil or compost by itself. It is designed for use in flower pots (hence the name). You can't really put soil in flower pots. It is too heavy, doesn't drain well enough and over time will pack down and turn into a brick. There's no such thing as "raised bed potting mix." But the square foot gardening folks, who want to get the maximum productivity from limited space, do sort of use their raised beds as big pots/ planters and fill them with potting soil type ingredients.

Technically mulch is any organic material you cover your soil with to help it hold moisture, suppress weeds. Mulching (ie covering your soil with mulch) is a good thing to do because over time the mulch breaks down to help feed the soil. Mulch in this sense can be fall leaves, straw, grass clippings, shredded paper, pulled weeds, etc. When you see bags of "mulch" in the store, it usually is bark chips. People cover their flower beds with bark mulch partly for ornamental effect (often the store bark chips are dyed) as well as above benefits.

Hope this helps! Welcome!
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gumbo2176
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Re: Different soils

I was in Lowes 4 days ago picking up 3 large bags of potting soil and just in front of me was a lady with a large cart that had 10 bags of "Raised Bed Soil" and several vegetable plants in starter pots. When I saw Raised Bed Soil written on those bags I almost busted a gut to keep from laughing.

I guess those folks that bag this stuff are looking at all aspects of gardening and trying to cover all bases with their own "unique" products designed specifically for each individual application. Horse hockey and no truth in advertising is what it really is.

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jal_ut
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Re: Different soils

Williams1, welcome to the forum. Top soil, that miraculous thin covering of the earth where plant roots reside, is a mix of clay, silt, sand, water, organic matter and a host of living organisms. It varies a lot depending on where it is found.
rainbowgardener, covered the basics. Please tell us what your interests are? Are you growing a garden? Pots and containers or on the lot out back?
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-

imafan26
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Re: Different soils

Be careful with bags labeled 'topsoil'. True topsoil is the first 4 inches of soil you find in a forest and it is usually full of critters and high in organic matter (humus). Most bagged topsoil is just plain dirt.

Most potting mixes do not contain any dirt. Although I do know some people who like to include a shovel full of dirt in their mix to add soil microbes which will be absent in a manmade product. Potting soils can contain anything from compost, peat moss, vermiculite, perlite, wetting agents, lime, and or fertilizer. They are lighter that soil, take longer to compact, and provide a good substrate to support root growth. pH is usually balanced with lime. The fertilizer in some potting mixes will last as little as two weeks or as long as 3 months (if they use osmocote).

Garden soil is pretty much compost and dirt. It is too heavy to use in pots and should be treated like compost.
Compost based potting soils like Hyponex should be banned. They should only be used for mulch or like compost. It is not good for pots.
Some people can plant in compost, but they must have really good compost and aklaline and salt tolerant plants. Most plants don't get enough nutrients from compost alone and most composts are alkaline and can be high in salt. Most plants like slightly acidic conditions.

All composts are not created equal. A good compost is made from a variety of materials; has been made well and has matured properly. Composts that are cold composted may not have gotten hot enough to kill weed seeds or pathogens so clean materials should only be used in them. Source materials need to have enough acidity and nitrogen so that as the nitrogen is used up the finished compost will not be very alkaline. Contrary to what most people think, most composts when analyzed are are alkaline and not neutral. However, composts can buffer pH so that the soil acts more neutral even when it is not, up to a point. Aerobic composts end up being alkaline. Anaerobic composts are acidic . Peat moss is an acidic compost created by the anaerobic decomposition of peat bogs. Peat moss has a pH around 3 which blueberries actually prefer, but most commercial peat moss has been limed to a pH of about 6.0 and wetting agents have been added because it is a fact that peat moss is very hard to wet without it. Peat moss with wetting agents are not organic. Peat moss is a natural mined product and is renewable but only if it is mined sustainably.

Mulch is used as a cover to slow down the weeds and keep the soil moisture in and can help with erosion. Mulch can be anything from dried grass clippings, leaves, rubber mulch, rocks, paper or plastic mulch. if you use decaying matter like grass clippings or leaves as mulch it is fine to leave that on top. Eventually it will breakdown and become compost. You don't want to turn in large amounts of bark, leaves, straw, or grass clippings into the soil before they have fully broken down because they will steal nutrients from the plants as the microorganisms consume the nitrogen fertilizer to breakdown the organic matter. Trench composting of vegetable scraps can be done in small amounts especially with added nitrogen because they break down fairly fast and you don't plant on the compost right away.

I never saw raised bedd planting mix. I know I can get a nusery mix in bulk from the local composting facility and it contains compost, soil, sand, cinder (for drainage), +- composted manure, and dirt. It would be a lot more expensive in bags than in bulk.

I have seen a patio mix, but it looked a lot like garden soil with fertilizer. It is not something I buy.

I usually make my own potting mix since I use so much of it and I have different plants that require different mixes. I usually make peatlite and add vermicompost when I have it. I use osmocote as starter fertilizer for the potting mixes. Succulents, citrus trees, and some orchids are in pure cinder. Fertilizer has to be added since cinder doesn't contain many nutrients. Orchids do better in baskets with no media. I have some orchids in cinder and some in bark. Hapuu is the best media but hard to find. I start most cuttings in perlite. In my veggie garden I add compost and sulfate of ammonia that is all I need according to my soil tests. I did add lime to my acidic plot and peat moss and sulfur to the alkaline plot to correct pH last year. I do also add the remains of the potting soil I don't resterilize to the garden since the pots have to start with a new mix.

I like a soil conditioner called gro power which contains humus. It is not high in npk, but feeds the soil organisms so plants are healthier and grow better. It is just a lot harder to find now.
Happy gardening in Hawaii. Gardens are where people grow.

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