Seen This In Your Potting Mix?


January 10, 2014

Text Fully Edited May 8th, 2018

By Eric Coulombe, President Garden Culture

Found a bunch of these semi-transparent balls in the bag while you’re potting?

NO NEED TO PANIC! Most of the time, it is slow release fertilizer.

Back in 2014, there were multiple complaints from gardeners who experienced infestations after using potting mixes. We apologize for the alarmist language used in our original post, as we like to help solve gardening problems, not make them bigger than need be. I have had fungus gnats mysteriously appear in my indoor garden in the middle of the winter. I never saw an egg. The problem is real, but finding a variety of different colored and sized balls on the surface of your potting soil is normal if the company includes a slow release fertilizer. However, if they do not, and you see something that looks like eggs, then you should be concerned.

If you’re using store-bought potting mix and having problems with insect pests in your indoor garden, you’re not alone. Along with other quality issues, getting free bugs with your potting soil seems to be a growing issue with several major brands. While most consumers confine their complaints to the place of purchase or may even be unaware there’s a problem because they’re only growing outside, there are numerous reports of bug-infested media. The other problem is mushrooms from all the wood and sawdust in the mix.

When you do come across various-sized balls that differ in color, they are most probably fertilizer designed to slow-release for the period stated on the bag, giving the plants much-needed nutrition. If they are in fact eggs, they could be anything from spider eggs to gnats, and some of the insect eggs or larvae you might not notice at all. And, the first sign of trouble will be insects suddenly flying around, or crawling up the sides of the pot when you water. The reason is that the bags have tiny holes in them which are necessary for the soil to breathe, and to keep mold from growing inside; potting mixes are not packaged totally devoid of moisture.

Where the bags are stored also has a lot to do with what is in them. Since most people buy this kind of stuff at big box stores, it was most likely stored outdoors. Just about any retailer would do this because the bags are weatherproof, and even freezing won’t cause any losses on a bag of dirt. Insect pests tend to be pretty small, making it an easy feat for them to get past the shrink wrap on a pallet and enter bags through the venting holes. They’re just doing what they’re supposed to do.

Furthermore, there’s really nothing manufacturers can do about the situation.

This forum discusses the same issue: Consumer Affairs

Images courtesy of Consumer Affairs.



Contributing Writer at Garden Culture Magazine
The garden played a starring role from spring through fall in the house Amber was raised in. She has decades of experience growing plants from seeds and cuttings in the plot and pots.

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