"The New Encyclopedia of Gardening Techniques" by the American Horticultural Society provides an in-depth look into gardening. This book contains details on getting rid of plant disease in the garden and preventing plant problems.
Cover Courtesy of Mitchell Beazley
Thin excess seedlings as soon as possible to avoid problems caused by overcrowding. Leave the strongest to grow: you may thin a row of seedlings several times.
Courtesy of Mitchell Beazley