top of page
  • Writer's pictureWisdom Preserved

How to start seedlings in flats (Mittleider Gardening)

Updated: Nov 1, 2023

This method used to start seedlings in the Mittleider flats is a great way to start the vegetables for my garden. It makes planting in bulk easy. We have multiple separate posts for the preparatory items needed for this step. Those include: how to make the seed flats, how to make the custom soil, and the pre-plant fertilizer.

Today we are going to start seedlings in flats.


seed flat

about 4 gallons worth of custom soil

1.5oz pre-plant fertilizer

1-1.5 gallons water

3/4″ x 3/4″ x 17″ board



Start Seedlings in Flats

The first step to start seedlings in flats is to fill the flat with soil.

The first step is to fill the seed flat with custom soil. Use a longer board to level off the top so the soil is completely flat. Then, add 1.5oz of custom fertilizer and mix it in. Next, the soil needs to be releveled.

When you start seedlings in flats make sure you water the soil.

Watering the soil is the next step. It will usually absorb anywhere from 1-1.5 gallons of water. It is best to wait a few hours before planting to let it absorb all the water you added before planting.

When  you start seedlings in flats make 8 furows in the flats.

Use your 17-inch board to make 8 furrows across the flat, about every 2 inches.

Add your seeds to the rows. Mittleider recommends limiting your number to no more than 600-800 per flat. This seems like a huge number but when you consider that you plant twice what you need, the numbers increase quickly. This flat is really just for germination. The seedlings will be transplanted to their own flat fairly quickly once they emerge.

Next, you add a small layer of sand or custom soil over the row of seeds. A general rule of thumb is to make the sand layer 2.5 times the width of the seed you planted.

Add burlap and water to the top of your flat that you used to start seedlings in flats.

Add a layer of burlap over the entire flat and water through the burlap. This keeps the soil and seeds from being disturbed when watering. This burlap will need to be removed as soon as the seedlings begin to emerge so the seedlings can get sunlight.


That is all there is to it. Then, you just water every day with plain water and wait for your baby plants to come up.

For our building a greenhouse videos, check out our Youtube Channel:

For other gardening tips follow this link:

Stir Gently.png

Top 9 Most Popular Videos at Wisdom Preserved

bottom of page