How to Sprout Seeds on a Sponge Garden

This time of year, the weather may be safe to plant seeds outside, but it may not be quite yet. My kids and I decided to experiment with sprouting seeds on a sponge garden.

These little gardens are the perfect way to spout seeds and get them started before it’s warm enough to garden outdoors. After sprouting our seeds, we moved them into little pots to continue to grow until temperatures outside heat up. 

What you’ll need to make a sponge garden:

• Sponges
• Fast-growing seeds (like chia seeds, grass seeds, or broccoli seeds)
• Plate
• Scissors

We ended up using broccoli seeds for our sponge garden, which did take a little bit longer to grow than some other kinds of seeds. Chia seeds, I think would be ideal, but we could not find them anywhere locally, and the purchase price online was surprisingly expensive. I think we were looking for seeds just a bit too early!

The first step is to build your sponge garden. Building the sponge house is fun all by itself! You can let your little builders get creative with this or follow our directions here.

We decided to transform our sponge garden into a log cabin. 

I cut the sponges into strips longways. We used about 2 sponges for the base, then one whole sponge for our cabin’s roof. 

Soak the sponges in water, and then squeeze out about half the liquid. 

Leave a little more liquid in the sponges than you would if you were using them to clean because we found that if our sponges were too dry, the seeds stopped germinating. 

Stack the sponge strips into a log cabin shape and top with the whole sponge. 

Sprinkle the seeds on top. 

We found that placing the seeds in the hole of the sponge helped keep them in place when the sponge needed watering. 

We keep the sponge watered by removing it from the top of the house and watering beneath the sponge. This prevented the seeds from rolling away before they took sprout. 

Put your seed cabin in a sunny spot, but make sure to keep it watered!

After about 3 days, you should start to see seeds. In about 10 days, your seeds will be fully sprout-sized and you can then move them to a container with soil. Or you can eat them with a salad! (It’s a great way to encourage kids to eat more greens!)

And that’s how you sprout seeds on a sponge garden!