Temperature

• Make sure the temperature levels are correct for the plant you want to grow. There are three main types of plants, including cool weather, tender and warm weather. Cool weather plants are good at tolerating cooler temperatures, so they can be planted as much as a month prior to the last frost. Tender plants will do all right in cooler temperatures, provided they are protected. Warm-weather plants won't tolerate cold temperatures at all, so you have to wait until temperatures reach at least 70 degrees to set them out. In general, most plants can be planted in the two-month window before and after the first budding and blossoming of trees, which occurs in the spring. The hardiness zone, listed on most seed and bulb packages, is a good tool for finding out what temperature is needed for growing a particular plant.
  
  

Moisture

• Check the moisture level. If the soil in your garden hasn't received enough precipitation to be crumbly when rolled in your hands, you'll need to wait to plant. Usually the moisture level of the soil reaches the correct level in the same months that temperatures for planting become appropriate, because the ground thaws and water falls as rain instead of sleet or snow. If you live in a particularly arid climate, however, you may have appropriate temperatures but simply need to add moisture to the soil for planting conditions to be prime. The hardiness zone list that is on the packages of seeds and bulbs often indicates not only the temperature levels but also the appropriate moisture levels for the plant you want to grow.
  
  

Crop Variety

• Look at the crop you want to grow. Some plants have a very short time for germination and thus can be started late in the spring, and others, like some perennials, have growth rates that require bulbs to be started in the fall before the plant is set into its main place in the garden. The best time to plant thus is determined just as much by the plant itself as by temperature and moisture levels.