Bio Dome Refill Sponges

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Plant a New Crop in Your Bio Dome with these Bio Sponges

This rooting medium is intended for use with Park's Bio Dome Seed Starter systems

Your Bio Planting Block will last a lifetime with these handy, economical Bio Sponges. When you're ready to begin a new crop in the Planting Block, first be sure that the block has been thoroughly disinfected (warm water with a splash of bleach is fine). Then soak the Bio Sponges you intend to use in warm water for a few minutes. They expand, revealing the pre-drilled planting hole at one end. Simply slip one seed into the hole of each Bio Sponge, place the Sponge seed-side-up in the cell of the Planting Block, and you're on your way to another bumper crop of healthy, strong, super-quick seedlings.

Bio Sponges are comprised of a combination of coconut coir, peat moss, and bio char and are now enriched with oilseed extract, giving your seedlings an extra boost of nutrition. You'll love the results!

3 different sizes available for replacement in the Original 60-Cell (sold in packs of 120), Jumbo 40-Cell (sold in packs of 80), and Whopper 18-Cell (sold in packs of 36) Bio Domes. Replacement Planting Blocks also available.


Skip Product Specs
Additional Characteristics Seed Starting
Restrictions *Due to state restrictions we cannot ship to the following:
Canada, Guam, Puerto Rico, Virgin Islands

Product Review Summary

Based on 6 reviews
The average rating for this product is 5 out of 5 stars
Overall Rating: 5.0/5.0

Customer Reviews

February 23, 2022


This shopper rated the product 5 out of 5 stars

I love the Park Seed Bio-Domes. I have 16 of them and they are super for starting seeds. I am a certified Master Gardener in Idaho and grow a lot of flowers. This year I started over 400 seeds and these Bio-Domes make my life so easy. We have white carpeting (YIKES) in my seed lab and my first years I had quite the mess, trying to use small starting pots with soil. These domes keep the humidity perfect and I can watch the roots develop as well. Don't hesitate - they are seriously the best for seed starting. I tend to like the 18 plug dome over the 40. But for marigolds and zinnias the 40 are best as I grow a lot of those.

Cathyanne from ID
October 30, 2018

Have worked great for years

This shopper rated the product 5 out of 5 stars

quick and convenient Very easy to replant in the beds. I have kept zinnias in this medium with open biodome for weeks while I waited to see how various flowers would thrive in the garden and then replace in the bed as some planted weak plants faultered. I clean the biodome with dilutedbleach at the end of season.

KY square foot gardener from KY
March 31, 2015

Very Good product

This shopper rated the product 5 out of 5 stars

Great product and very easy to use. Seeds sprout and grow easily by following the simple instructions and providing the proper light.

RonB from NJ
March 24, 2014

Happy with Bio Dome Seed Starter

This shopper rated the product 5 out of 5 stars

First time user of the Bio Domes and the growing of petunias. Very happy with results. I have had 85-90% success in Park Seed petunias. Germination in 4 days using grow light and heat mats. Yesterday started tomato and pepper seeds. I liked the no mess in the house and ease of watering. Will definitely be buying more to the five I already have.

Jeannine Loncar, Experienced Home Gardener from CO
December 21, 2013

Love the Bio Dome

This shopper rated the product 5 out of 5 stars

Parks Bio Domes are great. Follow the instructions and you can not go wrong. Parks also has a great support line.

New Grandpa from TX

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