Category Archives: Seedling Flats

Sawdust for the garden

We use sawdust in our Mittleider garden for our grow boxes and in our seedling trays.  Each year we top off the grow boxes before the growing season begins.  Today we made the trip over to a nearby town where a sawmill allows us to shovel our own sawdust for free.  They make pallets and are largely cutting inexpensive cottonwood trees for the lumber.  Any tree expect the black walnut provides a usable sawdust for a Mittleider grow box or seedling tray

 The sawdust is mixed with sand for both the grow boxes and the seedling trays.  For the grow boxes it is mixed at 3 parts sawdust and 1 part sand.  For the seedling trays it is 2 parts  sawdust to one of the sand.  Both are mixed by volume.  I’ll try and take some pictures that show the size of the particles.  Too large and too fine are both bad.

No idea how much wood they cut in a week, but this sawdust pile is massive, the picture truly doesn’t do it justice. 

Starting seedlings with grow lights and seedling heating mat

The seedling heating mat is plugged in and and the seedling trays are being brought up to growing temperature.  Today a bunch of our frost hard and moderately hardy plant will go into the seedling flats and get covered with sand.  A few items like our tomatoes will get started as well but will be protected from frost when they get moved into the garden. 

The pre-plant has been added to the seedling flats.  After the seeds are in and covered it will get watered with straight water through burlap until the seeds have begun to sprout.  Once they do the grow lights will get turned on and we will begin to water with constant feed.  

Kale, cabbage, broccoli, Brussel sprouts, collard greens, spinach, eggplants and lettuce will all get started today.  

Starting green bean seeds

We are late in getting these seeds started, but today we got enough seeds in grow boxes that we can do one full 30 foot grow bed in bush beans.  There are 9 rows in this seedling flat with 15 seeds in each row.

Notice the old vegetable can with sand and a white handled spoon sticking out of it?  IRS my preferred method to cover those seeds with wet sand.  It cover the seeds and the use the back of the spoon to even out the sand with the growing medium.  The sand, when wet, just doesn’t shake out of the can easily.  

After the picture was taken the rest of the seeds were covered and the seedling flat was covered with burlap.  We water the seeds daily through the burlap seeds sprout.  The burlap diffuses the water and helps prevent the seeds from being washout out of the sand.

Want to build your own seedling flats?  See this blog entry.

starting bean seeds in a Mittleider seedling flat

Building a few more seedling flats for seedling production 

Today the table saw came out and we quickly constructed a few more seedling flats.  It’s time to bump up a few of the vegetables under out grow lights, starting with the kale. They’re pretty simple to make and relatively inexpensive.  

The flats are 18″ X 18″. The instructions for building your own can be found on page 181 of the MGM book. We used the table saw to cut the two widths of the slats for the bottom of the seedling tray and a pneumatic staple gun to assemble each part. 

4 completed Mittleider seedlijng flats
completed seedling flat
conatucting a Mittleider seedling tray
Mittleider seedling flat

Building more seedling flats

The beans I recently started from seeds for my fall crops are growing like mad and will need to be bumped up before I transplant them in the garden.  To allow room for them to grow when we bump them up (transplant) we built a couple more seedling flats. 

 In your Mittleider Gardening Course book you can find a description and dimensions of the seedling flats on page 181.
The flat was filled with the same sawdust, sand and perlite mix that was used in the first one where our seeds are now growing.   The beans will be transplanted into the new flat soon.