Parks Double Bio Dome with 80 Jumbo Cells
The Revolutionary Seed-Starting System for Years of Perfect Germination -- Now in DOUBLE JUMBO Size!

Park's Double Bio Dome with 80 Jumbo Cells

Item # 96039
Buy 2+ at $44.50 ea
Item is sold out.

This "mini greenhouse" lets you control climate and conditions for best germination!

Bigger, healthier, better-rooted seedlings every time -- and twice as many of them!

A Park Seed Exclusive!
Other Items in this Series:
Park's Original Bio Dome with 40 Jumbo Cells Park's Original Bio Dome 60 Cell Seed Starter Park's Original Bio Dome with 18 Whopper Cells
Item Form Accessories
Additional Characteristics Greenhouses, Seed Starting
Restrictions *Due to state restrictions we cannot ship to the following:
Canada, Guam, Puerto Rico, Virgin Islands
Overall Rating: 5 Stars
Average Based on 4 Reviews Write a Review
Bio Domes - Jumpstart your planting season
Jay from very Northern Indiana from IN wrote (April 09, 2012):
I purchased one after reading other reviews here. Now making plans for 2 more. The first was set under a simple grow light (x2 wide) made from a plan I saw elsewhere at the Tractor Supply website. Had some seeds up in 2 days, all of them up in 5. Began without the dome so I could get the light closer. The lights were placed 1-2 inches above the plugs. The light is raised up a chain link every few days. In time I'll put the dome on and then wait for the plants to get big enough to be taken outside. They will harden off in a covered, raised garden bed. Gardening is just more fun when you can get this kind of a head start for Spring planting. Fast germination and rapid growth make for healthy plants to take straight to the garden. We plan on purchasing 2 more of these.
too fragile
disappointed from MO wrote (March 14, 2012):
I really liked the idea especially the higher dome. But unfortunately the dome is just too fragile. Don't hit the corner or it will shatter the rim.
Durable Product
Melissa from CO wrote (February 05, 2012):
I was using lasanga foil trays for my seed starting, until these. Very durable base. The lids are firm, quite strong, and the vents are handy. I wish the lid snapped, versus rested on the base, but I feel that is a minor issue. The cells are hard packed foam, but with care, they also can last a long time. I feel this product was a good buy and worth the money.
Good Buy for the Price
Boyer from MO wrote (December 04, 2011):
I have bought a number of seed starting kits for many years from department stores such as Walmart or Home Depot. So far the Bio Dome from Park Seed has been the best. The dome is made of hard plastic as opposed to the flimsy ones from the department stores. The vents on top are helpful since I use a heat mat to help warm my seedlings I can control the humidity levels within the dome by adjusting the vents. I don't use the "sponges" that are sent with the dome. Miracle Gro Potting Mix works better for seeds since it has a looser composition. I also use the same thing for cuttings. Also, I would recommend buying the Jumbo Cell dome. I've found it's a lot easier to pop my plants out of these rather than the smaller cells.

What are the differences between the various Bio Domes: 60-cell, 40-cell, and 18-cell?

The original 60-cell Bio Dome has a 60-cell planting block with 60 Bio Sponges and will produce 60 plants at one time. The 1" wide by 2 ¼" deep cells are larger than average, and a spacious 1 3/8" apart. The bio-sponges are the same size as the cells; 1" wide by 2 1/4" deep. You can grow and keep plants in the 60-cell bio-dome for 6-8 weeks before transplanting. Many varieties will just need 6 weeks until transplanting. Tomatoes and peppers would appreciate the full 8 weeks before transplanting. So, the original 60-cell bio-dome would be great for starting all of your favorite vegetable and flower seeds, with a larger number of plants produced at one time.

The 40-cell Bio Dome has a 40-cell jumbo planting block with 40 Bio Sponges and will produce 40 plants at one time. The cells are wider and deeper than the original 60-cell planting block and provide good spacing to maximize air flow. The cells are 1 1/4" wide by 2 1/2" deep. The Bio Sponges are also 1 1/4" wide by 2 1/2" deep. You can grow and keep plants in the 40-cell bio-dome for at least 6-8 weeks and some for up to 9-10 weeks, because of the wider spacing and cell/sponge size. It too would be excellent for starting all your favorite vegetable and flower seeds, with the added benefit of giving more room and time for larger plant development.

The 18-cell Bio Dome has an 18-cell whopper planting block with 18 Bio Sponges and will produce 18 plants at one time. It has the largest cells of any of the Bio Domes we offer and is great for growing extra-stocky transplants and even for rooting cuttings. The cells are 3" tall by 1 3/4" wide. The Bio Sponges are also 3" tall by 1 3/4" wide. You can grow and keep plants in the 18-cell Bio Dome for at least 8-10 weeks and some for up to 12 weeks, giving the maximum amount of growing time and spacing between plants as compared to the 60-cell and 40-cell Bio Domes. If you are looking to grow your favorite vegetable and flower seeds into large, stocky transplants for setting out in spring, then the 18-cell Bio Dome is the one you want to buy. It would be excellent for growing Tomatoes and Peppers.

How much water should be put in the Bio Dome and how often?

The beauty of the Bio Dome is that you cannot overwater! You just keep water in the tray and float the block. The larger the seedlings get, the more water they will use and you will need to add water more frequently as they grow. Initially, during germination, you may not have to water as frequently, because minimal water is being used and Bio Sponges will stay moist longer, so you may only have to water once every 1-2 weeks. Later, as plants grow and water use is greater, depending on the room temperature and the amount of light received, you may have to water more often -- possibly 1-2 times a week -- or as often as required to keep the sponges moist.

Bio Dome Instructions

Remove the Bio Dome Styrofoam blocks from the plastic wrap, keeping upright so that the plugs do not fall out. The plugs are ready to sow as they are!

For most seed types, place seeds into the pre-dibbled hole at the top of each plug. Tiny seeds that need light to germinate should be sown on the surface of the plug, not in the hole. Seeds do not need covering in the Bio Dome plugs. Each plug provides the optimum environment for germination.

Place the germination units in a favorable location as indicated on the seed packet.

To moisten the plugs it is best to soak them from the bottom. This can easily be done by putting water into the under trays provided and floating the Styrofoam blocks. It is not possible to over-water by this method.


Place the dome on the Bio Dome to maintain the humidity around the planted plugs. Keep moist until the seedlings emerge. Because of their composition, the plugs retain just the right amount of water. Less frequent watering may be needed and there is no danger of overwatering as with some other germination methods.

When you see that germination has started, open the vents on the Bio Dome. After the seedlings have emerged, remove the dome and provide more light. Use a grow light kept 1”-3” above the plants as they grow. This will prevent the seedlings from stretching and producing a weak plant. Brighter light will help keep the seedlings short and stout. Water as often as needed to keep the plugs moist.


Once the seedlings have developed their first set of true leaves, mix a weak fertilizer solution, following directions on the free fertilizer packet included with your Park's Bio Dome Seed Starter shipment. Water with this solution, instead of plain water; until the next set of true leaves develop. You can increase the concentration of the fertilizer solution once the second set of true leaves develop.

When the second true leaves appear the seedlings are strong enough to be transplanted. Transplant your seedlings, plug and all. To remove the plug from the block, poke out from the bottom and plant them where the plants are to grow.

If weather or timing delays your transplanting, often the roots will emerge from the bottom of the plugs. Prop up the blocks to allow some air space beneath them, until you are able to transplant but don't allow the plugs to dry. This builds a stronger root system within the plug.