Air humidity Gardening Herbs Saving seed

Gardening Uses for Silica Gel Packs

20171231A Silica gel THRIVE, flickr.jpg
No, don’t throw silica gel packs away: reuse them! Source: THRIVE, flickr

As you open your Christmas presents or indeed, many purchased items, you’ll probably find small paper packs labeled “Silica Gel: Throw Away, Do Not Eat.” They’re commonly found in clothes, leather goods, electronic equipment, medication, etc. These packs are added to such products as a dessicant in order to absorb any harmful humidity or musty odors that may build up during storage. And they’re highly efficient: silica can absorb up to 40 percent of its weight in moisture.

In spite of the label, though, you don’t need to throw them away, nor are they poisonous, despite what the “Do Not Eat” admonition* seems to suggest. You can, in fact, reuse them in many ways, including as a dessicant for anything you store away yourself for a few months: clothes, papers, photos, etc.

*Silica gel packs are not poisonous nor is their content in any way harmful to humans or pets. However, they could represent a swallowing risk, so store them out of reach of young children.

Gardening Uses

Here are a few ideas on how to use them for your favorite hobby:

20171231B HC.jpg
Add a pack to stored seeds. Source:
  • Add an envelope of silica gel to the container in which you store your leftover seed packs, then store the sealed container in the refrigerator. Seeds best retain their germination capacity when they are stored under cool, dry conditions.
  • Use them to help dry flowers faster and to prevent mold as they dry.
  • Place them with your dried herbs to reduce mold and mildew.
  • Use them to dry leaves (of herbs, for example).
  • Tape a pack to the inside of the lid of granular or powder fertilizer or pesticide to prevent condensation and clumping.


Silica gel packets don’t last forever. They’ll stop working once they collect as much moisture as they can. In most gardening situations, they should be good for at least one year, but after that, you’ll have to dry them out again. To do so, heat them in the oven at 200? F (95? C) for about 2 hours, then let them cool and store them inside an airtight container until you need them again.

Drying silica gel packs. Source:

You can also reactivate silica gel packs in a microwave oven, but that’s more complicated, as it doesn’t evacuate humidity as well as a conventional oven. Try heating on high for no more than 2 minutes (too much heat can damage the silica gel). If the envelope feels moist, the gel is not dry enough. Let cool 10 minutes, then heat again. It may take three to five sessions to dry it correctly.

Silica gel packs: for once, ignore the warning label and reuse them!201712 Silica gel THRIVE, flickr

1 comment on “Gardening Uses for Silica Gel Packs

  1. Pingback: When Fertilizer Turns to Rock – Laidback Gardener

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