Mixing constant feed for seedlings
If you are starting seedlings you will need constant feed. After your seeds have germinated the seedlings require a smaller dose of fertilizer than what would be applied in the garden. To give them a full dose of the weekly feed in a small container would burn them.
The MGC Book, on page 183 calls for the mixing of 1 ounce of the weekly feed fertilizer to 3 gallons of water. The nutrients do not dissolve immediately. Typically we will mix up a new batch and allow it to sit overnight to ensure everything dissolves.
If the constant feed is needed immediately one could add the weekly feed to a small amount of hot water and stir until dissolved. Add that solution to your bucket with 3 gallons of water and stir before using.
What containers can I use for the constant feed
My favorite container for solution is an old rectangular laundry detergent bucket. The shape makes it ideal for getting up close to the edge of the seedling table and our seedling flats. We can get the constant to the seedlings without slopping the liquid every where.
You can see the side of my bucket below. A measured 3 gallons of water was poured into the bucket. Then the water line marked on the outside of the bucket with a marker.
If you will have a LOT of seedlings then a plastic barrel or trash can with a lid would work to hold your constant feed. Avoid using metal containers, the solution will cause rust. To use the constant feed from a large container one would simply stir the solution and dip the watering bucket into the barrel.
The special device for watering seedlings with constant feed
A sprinkling can is simply a can with holes made with a small nail and hammer. For our own use here at home we took an empty 16 ounce can of green beans and made the holes. A small nail like the one shown below is ideal.