=Experiment.=--Plant seeds of corn and beans in each of two tumblers; set one out of doors in a cold place and keep the other in a warm place in the house. The seeds kept in the house will sprout quickly but those outside in the cold will not sprout at all. This shows us that seeds will not sprout without heat. If the weather is warm place one of the tumblers in a refrigerator. Why don't we plant corn in December? Why not plant melons in January? Why not plant cotton in November? The seeds of farm crops may be divided into two classes according to the temperatures at which they will germinate or sprout readily and can be safely planted. Class A. Those seeds that will germinate or sprout at an average temperature of forty-five degrees in the shade, or at about the time the peach and plum trees blossom: Barley Beet Parsley Oats Carrot Parsnip Rye Cabbage Onion Wheat Cauliflower Pea Red Clover Endive Radish Crimson Clover Kale Turnip Grasses Lettuce Spinach These can be planted with safety in the spring as soon as the ground can be prepared, and some of them, if planted in the fall, live through the winter. Class B. Those seeds that will germinate or sprout at an average temperature of sixty degrees in the shade, or when the apple trees blossom: Alfalfa Soy Bean Squash Cow Pea Pole Bean Cucumber Corn String Bean Pumpkin Cotton Melon Tomato Egg Plant Okra Pepper We are now ready to answer the question: What conditions are necessary for seeds to sprout or germinate? These conditions are: The presence of enough moisture to keep the seed thoroughly soaked. The presence of fresh air. The presence of more or less heat. This teaches us that when we plant seeds in the window box or in the garden or on the farm we must so prepare the soil and so plant the seeds that they will be able to obtain sufficient moisture, heat, and air for sprouting. The moisture must be film water, for if it is free water or capillary water filling the soil pores, there can be no ventilation and, therefore, no sprouting. SEED TESTING In a previous experiment (page 73) the seeds planted in the wet clay did not sprout (see Fig. 38). In answer to the question, "Why is this?" some will say the seeds were bad. It often happens on the farm that the seeds do not sprout well and the farmer accuses the seedsman of selling him poor seed, but does not think that he himself may be the cause of the failure by not putting the seeds under the proper conditions for sprouting. How can we tell whether or not our seeds will sprout if properly planted? We can test them by putting a number of seeds from each package under proper conditions of moisture, heat and air, as follows: