Always Pre-Moisten Potting And Seeding Mixes


I like the modern potting and seeding mixes – the high quality types from Miracle Gro, Burpee, or the custom blends from locally owned garden centers. When I was younger, we used to make our own mixes, blending one part soil, one part peat moss, and one part aggregate (sand, perlite, or vermiculite.) But I’ve found today’s mixes work better, and they’re more convenient.

The top-quality potting mixes and seeding mixes are quite light. In fact, I’ve discovered that you can tell the quality of a mix by lifting the bag. Poor quality mixes are usually quite heavy compared to the better quality types, which is helpful when shopping. Just lift the bags.

When you open the bag of a top-quality mix, you usually find them very dry, which is fine. But it’s quite important to moisten the mix before using.

Why it’s important to moisten potting and seeding mixes before use:

  • High quality mixes are packaged dry, and they can be difficult to rewet if used straight out of the bag.
  • Dry mix tends to float when first watered, if used without pre-moistening.
  • If seeding mix is used dry, seeds will tend to float when the seed tray is first watered, making a mess of the seed tray.
  • If houseplants are planted into dry mix, their roots can suffer, as they resent contact with powder-dry material. Contact with dry material can injure tender root hairs, as the dry material struggles to absorb moisture.
  • Seedlings and rooted cuttings transplanted into dry mix can be injured as their young roots contact dry material.

Best way to use packaged potting and seeding mixes: Moisten first.

  • A day or two before intended use, open the bag of mix. You can empty it into a washtub or large plastic tote for wetting, but I just add water directly to the bag.
  • Warm water tends to be absorbed a little faster.
  • Begin adding water to the mix. Stir by hand, adding water as you go. The amount of water to add is difficult to precisely say. The mix should not be muddy-wet or overly sticky. But it should be mellow-moist. Mix thoroughly, moistening all dry spots.
  • After mixing, close the bag, or cover the container, and let the moisture permeate the mix for at least a day, then it should be ready to use, and nicely moist.
  • When using the pre-moistened mix for potting, seeding, or transplanting, the first watering is much easier. Although the mix has been pre-moistened, it’s always important to water immediately after seeding or transplanting.

Happy Gardening! 



7 Responses

  1. Teri Smith

    Don, you tell us so many things that are so helpful that I have never heard before. Keep up the great work!

  2. Jan Kaltenbach

    I was always told to wear gloves when handling the dry mixes-do we need to do this when mixing??

    1. Don Kinzler

      Hi Jan. I don’t wear gloves, just because I’m not used to wearing them. I don’t know of a particular reason why gloves would be recommended, or of any harmful material that would affect skin. I avoid breathing any dust. Sometimes it’s difficult to separate truth from rumor when we’re told things. I’m not sure about wearing gloves. I wonder if some people’s skin might be sensitive to materials in the mix? Thanks.

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