by Amber

Seen This In Your Potting Mix?

Text Fully Edited May 8th, 2018

By Eric Coulombe, President of Garden Culture Magazine

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.

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  • lola says:

    What happens if it squishes/releases/squirts into your eye? Can the larvae attach itself to the eye protein?

  • Wendy says:

    Hi sorry but is that a fertiliser ball in the pic ??

  • andrew jones says:

    Certainly not fertalizer it appeared on top and thier was evidence of slug or snail trail. It would have had to moveor floated threw 6 inches of peat moss. And appear clean on top of the soil.

  • Julia says:

    These squishy clear balls came in our potting mix. And now we have what looks to me like caterpillars wrapped in dead leaves crawling out from our roses. Could it be that they are actually caterpillar eggs? (Or slug–what everyone here is calling them?!)

  • Kitty says:

    Oh geesh!!! I just planted my vege trug and used Miricle grow. It had lots of yellow balls that my husband saw and said “these are bug eggs”!!! He squeezed and popped one open.
    I was in such a hurry to plant the trug i just chose to ignore them and move on. I AM SO SORRY!!! YUCK!! I had to take a ferry to town and had lugged six 56 lb bags of (bug infested) Miricle Grow from Lowes.
    Now what to do??
    My vegetables are growing?? Do i judt dump it out and start over???

    • Eric Coulombe says:

      Don’t panic! It could be eggs but there is a good chance it is not. What did your husband see when he squished it?
      Fertilizer balls can be filled with moisture and could be mistaken for eggs.

      Take a bunch out, put some in a empty glass container, not sealed with some soil and do a little experiment. See what grows or does not. If you have a good loupe or magnifying glass try to cut one open gently and take a look at what is inside.

      If those balls are eggs and they do hatch or you see some weird baby bug in the egg, well then yes this will not be the best experience and starting over is an option, but not the only one. Really depends what the bugs are I guess.
      Please keep us posted and let’s hope that they are spent balls of NPK.

      Good luck!

  • Scott Ishman says:

    I have been working farming for a year now, and I have tons of those in my worm bed. In my case they are worm eggs. To be specific red wiggler worm eggs. I did not start with commercial soil I started with bio char and kitchen vegwaste.

    • Serena Sayers says:

      Thanks for sharing! 🙂

    • Eric Coulombe says:

      We love red wigglers. Perfect example of good eggs in your soil. I would be pretty surprised to find them in a bag of commercial soil mix, but I’m sure it has happened. Especially if you are buying anything with worm castings in it.

  • Lar says:

    WE noticed the various size egg like material in our miracle gro. They kind of looked like tapioca. Some were bigger and the outline of some sort of bug inside, could be seen. We did not have any other soil available and found that many we did buy , would be opened and immediately little flying insects would start exiting the bag. We then sifted through the bag dropping all the eggs into a solution of vinegar or squeezing them as we went. We’ll gladly save a bowl full for the ahole at miracle , if he’s like to chow down on them.

  • Anonymous says:

    I use coir / perlite I mix myself. These are not in the mix when I expand the coir and mix in the perlite. Every once in awhile I will find these in some of my plants I have started from seed or cuttings (so I know it was not fertilizer added to the planting media) I placed some of these in a sealed plastic bag andf some hatched but they died before I could ID what they were. These are eggs and not always from the potting mix. I only grow inside and the only pests I’ve had were fungus gnats, one plant had aphids (which was quickly dealt with) , and I’ve seen a few box elder bugs inside. While these are similar to box elder eggs, the box elder bugs are oblong.

    • Eric Coulombe says:

      Fungus Gnats have found their way into my indoor garden in bags of coco more than once.

  • billiejo r lear says:

    I landed on your site doing research on fungus gnats. We have a huge break out. We purchased miracle grow. While I do not dispute that gnats came from miracle grow, I have had MANY well educated people on this subject inform me that due to taking your advice, I was removing the balls put in soil for fertilization. YOU really need to look at what gnat eggs look like. THIS is not it. You are telling people to remove the very stuff that keeps their plants healthy. I would have expected different from someone speaking for a magazine called Garden Culture. 🙁 sad to see this.

  • Deb says:

    I have had Miracle Grow potting soul infested with fungus gnat larvae. When I opened the bag, there where even adults flying around in there! I also had a bag with a bunch of mushrooms growing. Needless to say, I don’t buy that brand anymore! But the fungus gnat problem prompted me to search online. One method I explored was to microwave the bag of soil before using! It will kill anything alive in there. Worked great! Sorry I forget the directions, but you can look it up!

  • antonella says:

    thanks for this info, I am not an expert gardener and Ii chanced here because once again i googled roots pots ‘little yellow eggs/spheres. I started finding these yellow spheres last year- to cut a long stiry short: these spheres are clustered around roots, I think they are root eating slugs like you suggested. i have a large terrace and never had problems until last year when i actually found enormous slugs in the soil after investigating the death of many of my plants. The different circumstances I can mention in respect to past years where i had never even heard of slugs, were 1. extreme heat in Italy last summer 2. drought 3. many many beetles flying around . The soil I use is purchased in the same conditions as you state above, i am positive the soil comes complete with pests also here in italy. Also I am sure they are root eating slugs, yuk. Anyway could the problem have something to do with beetles? The slugs I discovered were whitish and moved in a continuous circular burrowing motion YUK. I found them again this year as I am preparing to plant new flowers. They were clustered around old roots in a pot i had left outside all winter! I threw the soil away. I really don’t think they are fertilizer balls.

    • Callie says:

      Hi Antonella,

      If you have grubs (not slugs) they are definitely from beetles, this is easily determined because grubs have legs and aren’t slimy, while slugs have no legs and travel on slime.

      And to make sure that no beetles visiting your garden leave eggs behind, you can cover the potting mix surface with weed fabric so they can’t dig and deposit. Slugs, on the other hand, commonly enter the pot from the bottom drainage hole. Raising the pot a couple inches from the ground or patio surface can help keep them out. There’s some other ideas on battling slugs here.

      But as you say, it’s also possible they came in the potting mix. Natural is not the easiest thing to control!

    • anTonella says:

      thanks callie, yes in fact i meant grubs not slugs- i have no idea if the blighters have legs, they move in a fast circular burrowing movement and I threw everything out screaming all the while. I know gardening isn’t what I do because I am squeamish and thats not what gardening’s about, really- but I love flowers and birds and I do try. Anyway, thanks for the tips

  • Anonymous says:

    In use a mix of coir and perlite that I mix up myself (inside only) and use miracle grow fertilizer (okay- sue me- works great for my plants) and I’m also seeing these eggs occasionally. I picked some of them out, placed them in a little coir mix and placed in a sealed plastic bag – they hatched although died before I could identify them. These little round balls are eggs.

  • Clarke Tee says:

    They are bugs eggs from my experience. Spinosad insecticide works but you need to keep the whole container submerged for 30 minutes.

    • Tammy Clayton says:

      Hi Clarke,

      Thanks for stopping by and sharing your input. And an organic-approved application too.

  • Alterego says:

    Message from my neighbor Who is a horticulturist: Actually the yellow pellets are slow release fertilizer. The white pellets are perlite and are an expanded mineral meant to create porosity in the growing media.

    If you notice gnats with your indoor plants go the the store and get neem based products and do a soil drench with double the label rate. Also be sure to let the soil dry out between watering, that will help with gnat prevention.

  • Some guy says:

    Tammy – you’re mistaken. Osmocote comes in several different shapes and colors. Those are almost certainly Osmocote pellets, especially since we know Scotts adds them to their potting mix.

  • Anna says:


    May be a silly questions but I’ve been growing vegetables this year for the first time so forgive me. I’ve just found a load of these clear beads in my spring onion soil/compost. Is it still safe to eat the spring onions?

    Thank you

  • Chloe says:

    What if it gets in your eye

    • Tammy Clayton says:

      If potting soil gets in your eye, it’s best to flush it out like any other foreign matter. Dirt, leaf bits, whatever – flush it out with clear water from the faucet.

  • Cody Northcutt says:

    After reading comments I have not seen any eggs I know kno they are for fert , perfect round pellets and yes I think I would of noticed them first but now since watering they have grown lol but I was actually wishing for bugs bc then my fly trap could eat away and he is outdoors so It would be fine but kinda worried when I read root eating slug

    • Amber says:

      Hi Cody,

      Yes, if they are perfectly round, filled with milky liquid, and have a hard center when popped – they are fertilizer.

  • Cody Northcutt says:

    Bought some peat moss for my fly trap and used it then after a few days messing with my plant and taking car of it I start to notice these and I thought maybe my venus had seeds (not knowing what they looked like) squeezed one and it squirted

  • Sara says:

    Those balls are swelled up osmocote particles. Its a slow release fertilizer. Hence why they are perfectly round when dry and then swell because of water. That is why you can pop them and there is liquid in them. What you have pictured there are osmocote particles that have swollen and are releasing nutrients into your soil.
    All you have to do is google osmocote fertilizer swells because of osmotic pressure and you will see numerous scientific articles on the process.That is why the particle is called osmocote because it releases using “osmotic gradient” Osmocote is a coated fertilizer that releases through a change in moisture. You can also do your own at home experiment and take a dry osmocote prill and put it in water. You will then see after a day they look exactly what you took a picture of. All osomocote particles swell when moist and swelled osmocote particles when squished will puncture and release a liquid.

    • Amber says:

      Thank you, Sara from Scotts Miracle Gro for clearing that up.

      However, it does leave one with a new concern over the lifetime of the fertility though, since it is time released and activated by the moisture that causes it to swell. Which means that after being stored where it’s gotten wet the fertilizer is already partially spent. So it’s not a good idea to buy any potting soils left over from last year, or even later in the season.

      And there are still bugs plaguing consumers from outdoor storage of materials and the bags at retailers, even if some or all of these liquid filled balls are osmotic fertilizer.

      Nice to learn about, along with the knowledge that Miracle Gro potting mix contains a different brand of fertilizer. The wonders of labeling. Last time I bought slow release Miracle Gro in the shake form it was all granular. No osmotic prills at all.

      Gotta remember to check for a ‘Contains Osmocote’ statement on a bag of Miracle Gro potting mix next time I visit a big box store.

    • Frankie Kendall says:

      How do you get rid of the infestation? Most of my houseplants are riddled with them. I used Miracle Grow potting soil to plant them, which after reading the article… Makes sense… Dang it!

    • Callie says:

      Hi Frankie,

      What kind of bugs do you have now? Knowing what you need to eradicate guides how you can get rid of the problem.

    • Fireonthe mountain says:

      They are not an infestation, they are time release fertiliser.

    • Sharon George says:

      The photos of the time released fertilizer are DIFFERENT from the little translucent balls in the potting soil. The balls are perfectly round, the fertilizer ‘balls’ aren’t. Look again. It’s NOT fertilizer.

    • Deedee Pine says:

      I just repotted my root bound Sansevieria and found pockets of the hundreds of bead like white eggs. Not fertilizer, not vermiculite, EGGS! The problem is what kind of eggs….Grubs? Snails? Earthworms? Now Roaches? All the internet pictures of them look the same. I spread the potting soil out in the sun to dry up and kills the eggs. Guess I’ll never know what they are….Probably should have put some in a covered container and hatched them…oh well…too late.

    • Freon says:

      How do you know if they are bug eggs?

  • Sam says:


    They claim that these are not eggs of any type but time released fertilizer pellets.
    I came to this thread wondering the same. I am not a bug expert or fert expert so we have a conflict with the information. I looked up Gnat eggs, they are oblong and not quite the same. Again, not an expert but you need not be a weatherman to know its raining. How about some follow up on the matter?

    • Tammy says:

      Hi Sam,

      The slow release fertilizer pellets, such as Miracle-Gro and Osmocote, do look similar to some of these bug eggs. For a number of years I paid them no attention at all, thinking they were fert, until a high school student pointed out that there were spider eggs in the soil she was potting nursery stock with. No wonder it got soft, squishy, and kind of translucent!

      So, take a look at those little round things. They might be milky white but somewhat see-through, or yellowish. They aren’t all uniformed size like machine-made fertilizer pellets, and you can pop them easily by squeezing them between your fingers. Fertilizer doesn’t pop, squirting liquid under pressure! Eggs do.

      That “expert” is mistaken, misinformed, or a damage control operative put in place to skew public mindset.

      Check out the fertilizer images here, and you’ll see what the other author is referring to – albeit, in error or on a spin mission.

  • Adeline says:

    I bought a bag or Orchid Potting Mix. My local supermarket stocked a few in their floral department. When they knocked the price down from $10.99 to $1.99, I excitedly obliged. Great buy!? Not quite. I replanted all 3 of my orchids and used a bit of the mix for my succulents. I saw the balls and I picked most of them out; I just didn’t like the look of them. I obviously didnt get them all. I now have Roaches. Sea roaches, to be specific, in Cleveland. I can’t…

    • Adeline says:

      I forgot to say: thank you for the picture of those eggs. The “potting mix as the culprit” was only a working theory until I found this. Invaluable information. Graci.

    • Amber says:

      Well, now we know that Orchid Potting Mix or something in it comes from a coastal region.

      I don’t think it’s avoidable, this bug eggs in the potting mix. Bugs go wherever they want to – no manners, no rules. Potting mix materials aren’t sterile like Bandaids, or stored where no bugs can roam like food. They mix and package millions of bags of various kinds and brands of potting mix each year. The mountains of ingredients have to be stored outside. Then the bags themselves in storage don’t need to be protected from hot and cold.

      Bugs, being bugs, are just doing their thing, and the more people who grow indoors, means the more people who will have bugs hatching in their house. To guard against it happening, you have to heat the potting mix to a temperature that will cook the eggs, but not catch the potting mix on fire. Safer than fumigating with nasty chemicals.

      Smashing might work too. Spread thin on a hard surface and pounded with a brick or something similar. Would smell better than baking for an hour, but maybe a bit time consuming.

  • Jori Lampe says:

    Those little balls kill my garden two years ago I knew they weren’t plant food I knew what they were they were some type of a slug this year they were in my friends garden and their Roots have been all eaten their whole crop gone. The little balls are some little type of Slug and they are root eating slugs they will eat your roots especially if you start your garden with the seed it will not grow because they will eat the tender roots and it won’t grow anything. What I’m searching for now is how to kill them in the potting soil and still be able to grow your vegetable garden. I’m having a hard time identifying the name of them.

    • Tammy says:

      Hi Jori,

      Thanks for sharing that info. You’re the first person to report it as slugs, though I wonder if they’re not all living eggs, because I’ve never had slugs hatch in the seedling trays. I’ve also noticed that there can be both round white eggs and larger round translucent yellow eggs.

      And since slugs are too large to squeeze through air holes in the bag, they were packaged with the mix. Somehow the moisture level inside the bag seems very low in terms of providing a good environment for slugs to live in – as an egg, or after hatching. I guess it depends on where it was stored and how wet the weather has been.

    • Zeb says:

      They are stink bug eggs

  • Ted Anderson says:

    I have found these “eggs” in the bottom of the cocoafiber liners when I empty them to put in fresh potting soil, so I long suspected they were not fertilizer additives. Today I found them in my bag of TurfKing potting soil, so I stopped using it and returned it for another brand.

    • Callie says:

      Wise move, Ted. Especially, if you’re growing indoors. Outside, you simply can’t stop nature from doing it’s thing, which is where all stockpiled bags of soil and potting mix are stored until they arrive on your local garden center and store shelves. Its not like moisture and exposure to the elements will ruin it, so why sacrifice warehouse space?


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.