Sweet corn is ripe and ready to harvest when the top of the ear is round, not pointed. African Violets will bloom much longer if your stick a few rusty nails into the soil. To grown pole beans without constructing a trellis, try growing them next to Sunflowers and they will happily climb the stalks without hurting the Sunflowers at all. It makes a great natural bug repellent. If the stem of a carnation plant is bent into the soil it will form a new root.
Small plants can be susceptabile to a fungal disease called damping off.
To prevent disease from overwintering in your rose bed make sure you remove all dead leaves and debris. Do not use a mulch, dispose of it. To get more out of your garden harvest, plant seeds or plants in two week intervals. Try not to water your garden with an overhead sprinkler. It wastes water and wet leaves can invite diseases much more easily.