Substituting for potting soil?

When I buy potting soil, I usually buy alot and don't feel like paying upwards of $7 per bag, which aren't very big.

They sell big bags of garden soil which is ALOT cheaper and seems to be very rich, can I use this instead? Of course I'll add some material to aerate. But what exactly is the difference between garden and potting soil?

And, can I mix in some mulch into it? It makes the mix alot looser and some of the more expensive potting soils I've bought had mulch seemingly already mixed in.

Edited to say that I also add in peat moss.

This message was edited Nov 13, 2004 3:59 AM

The problem with using garden soil is that if it isn't sterilized you could be adding weed seed and other pathogens to new pots, seeds, and seedling that don't have the capability to combate them. If it is sterilized, then there are no beneficial bacteria, so additional fertilization is needed, and the sterilization process (baking) tends to make it rather cakey and heavy, reqiring even more aeration material to balance it, I sometimes make a 50/50 mix of finished compost or humus, and vermiculite or perlite to use as potting soil. So if you use large quantifies of potting soil and can buy or make the ingredients for potting soil more cheaply than buying it already mixed, you can save some money.

I think you're right now that I think about it.

We mix our own "blend" at work. Most of the potting mixes contain a lot of peat or bark which causes them to dry out quickly.
We mix two parts potting mix with one part bagged topsoil. Never had a problem with weed seeds from the bagged top soil.
We don't use this to start seeds but we transplant the seedlings after germination.

Paul

Soilless mixes for potting cause plants to be nitrogen deficient as there is not residual food allowed to absorb if there is no soil. As a grower I have never liked soilless mediums for that reason as well as most plants are very hard to keep moist enough to not develop scars from lack of water without a fancy drip irrigation system. The nitrogen deficiency is not that noticeable until you put two plants together - one grown in soilless mix and the next in bonafide dirt. It will appear that you have two very different plants in the leaf color alone. But because you cannot control the rain, pots do need sharper drainage than a nice 50/50 peat topsoil mix can allow. I like to mix in either vermiculite of fine shredded hardwood bark, the amount of which depends on how much moisture retention each plant needs. I never plant without adding Osmocote, Wonder Pellet and Nature's Secret which are beyond wonderful for lusher faster growth of all parts of the plant as well as allowing them disease and stress resistance. The Dept. of Agriculture Inspector has deemed my plants to be the best in her 2 county region (she uses my feed reipe at home now too). You will find it much cheaper when hand mixing your potting medium and using real soil over that stuff they sell in bags. If I used that my plant prices would have to be quite a bit higher.

I've heard of Osmocote and have used it in the past but I've never heard of Wonder Pellet and Nature's Secret.

I start my seeds in half perlite, half peat and transplant to regular potting soil or plant in the ground. I often feed with Miraclegrow or something else during the "growing" seasons but not during winter and fall, I've been told to refrain b/c it could burn the dormant plants. I feed my orchids and bananas year long but with different dillutions.

Obsessed, if you added some superthrive, I think you're formula would be complete. That stuff is GREAT! My passifloras love it and I think out of all my plants, they've reacted the fasted to it but all my other plants look better with it too.