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Pre-Sprouting Seeds: 101

Pre-sprouting means you are sprouting the seeds in the absence of soil, and then transplanting the 'live' seed with a bit of root to soil, compost, or vermiculite. The two most common methods of pre-germination are moist paper towel and gel. While many gardeners will ONLY use seeds prepared for the current growing season, what if you have some older seeds? Would you risk planting them and hope that they will grow? If you pre-germinate them, you can tell right away which seeds are viable and which are ready for the compost heap. Talk about saving time and valuable space in your vegetable patch.

Pre-Sprouting Methods

The basic way to pre-sprout seeds is very simple.

  1. Moisten two-three sheets of paper towel, not dripping wet just wet.
  2. Lay one layer of paper towel in a shallow Tupperware container*
  3. Spread the seeds out evenly
  4. Cover with another layer of moist paper towel
  5. Place the container in a warm spot, 70-75 degrees F is ideal
  6. Check the seeds daily, most seeds will start to germinate in 1-2 days
  7. Re-moisten if needed, you do not want the seeds to dry out

Once the seeds sprout roots it is time to transplant them to starter pots or sow them into the ground. Theses sprouted seeds are extremely fragile you do not want to break the roots that have formed. If the germinated seed has a little bit of paper towel stuck to it, that is ok.

*As an alternative to the Tupperware, you can lay the seeds on a single layer of paper towel and make little seed packets that can be placed in zip top bags that are only closed about ½ way.

The advanced method of sprouting seeds involves making a gel. First, mix 1 cup of water with 1 teaspoon of cornstarch. Let the mix come to a boil and start to thicken. Pour the mix into a shallow bowl, a pie plate, works well too. Spread the seeds evenly over the gel and cover with plastic wrap. Place the bowl in a warm place near a window for some indirect sunlight.

As soon as the seeds start to sprout roots, it is time to plant them. Take the pie pan outside and spoon the seed, with some of the surrounding gel into a ½” deep hole and cover lightly.

If you are up for a little adventure, there is one more method of planting you can use with the gel. Pour the gel mixture into a zip top plastic bag. Pour the seeds into the gel and mix around to distribute the seeds evenly. Zip the bag about ¾ of the way shut so some air circulates. Once seeds start to germinate take the bag outside and get ready to plant. First, dig a trench about ½-3/4” deep. Then cut a slit in a corner of the bag, and slowly squeeze the gel/seed mixture into the trench. Cover lightly and voila you have planted a row of pre-sprouted seeds.

Crops that work well with pre-sprouting are cucumber, tomatoes, peas, carrots, corn, parsley, pepper, eggplant, cabbage, broccoli, cauliflower and beet root. Beans can be pre-sprouted, but it is best to sow them directly as they have large cotyledons full of starch, and germinating beans are extremely susceptible to cracking.

If you are growing in a greenhouse, or a backyard vegetable patch, pre-sprouting seeds can shorten your growing window by days or even weeks. In some climates, where the growing window is short for things such as corn this can mean the difference between harvesting crops or watching them die from the first frost.

Happy planting! Feel free to post pictures of your pre-sprouted seeds on our blog or our Facebook page.