This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
When growing flower plants from seeds, start them in halves of shells from hard-boiled eggs. When the time comes to transplant them, they can be easily removed by allowing the dirt in the shell to become hard and then breaking off the shell, whereupon the plant is placed in the ground.
A pasteboard box provided with holes large enough to support the egg shells can be used to hold them, unless egg crates are at hand. Two large seeds such as nasturtiums and sweet peas can be planted in one shell, and four seeds of the smaller varieties. - Contributed by Katharine D. Morse, Syracuse, N. Y.