optimal temperature for seed germination flower seed germination temperature chart

optimal temperature for seed germination flower seed germination temperature chart

Planting Seeds Temperature

Warmer temperatures speed up chemical reactions and, conversely, cooler temperatures slow them down. Those chemical reactions help break down the protective seed coat and tell the seed that it’s time to wake up and start growing. For a cool-season leafy crop like spinach, the ideal temperature for germination can be as low as 50 degrees Fahrenheit. For heat-loving tomatillos, the minimum desired soil temperature is 80 degrees.


The anticipation and excitement that come from sowing seeds for a favorite flower or vegetable can lead to disappointment weeks later when many, if not all, of those seeds have failed to germinate. While many factors affect germination — from the age and quality of the seed to the depth of planting — the most challenging for gardeners and often least understood is soil temperature. Learning the best soil temperature for seed germination will go a long way towards your seed-starting success.While there is can be variation from one seed type to the next, most seeds for warm-season edibles prefer soil temperature between 70 and 80 degrees Fahrenheit (21.1 and 26.7 Celsius). When the soil temperature in your garden is too cool — or too hot — seeds may take longer than expected to germinate or will never germinate at all. Whether direct sowing seeds in the garden or starting seeds indoors, achieving the optimal soil temperature before planting will greatly increase the germination rate and also result in more vigorous plants.

So how does a gardener know when the soil is warm enough to plant? Dr. Jerry Parsons, Extension Horticulturist at the Texas Agricultural Extension Service, has identified what he calls a "realistic" soil temperature for germination. This is a soil temperature at which gardeners can expect good germination and strong early growth. Germination rates may be at 70 percent rather than 100 percent, but you can just sow the seeds a little more thickly.A seed is a miracle waiting to happen. The embryo comes pre-packaged with a food supply and the vital genetic information needed to become a plant just like its parents. Seeds exist in a state of dormancy, absorbing oxygen, giving off carbon dioxide, and slowly using up their stored food reserves. During this process the seed continually monitors the external environment waiting for ideal conditions specific for the particular seed. Once the ideal conditions occur, the seed breaks dormancy and germinates. The seedling gathers energy through its leaves by the process of photosynthesis and absorbs nutrients and water from the soil through the roots. As gardeners, our goal is to provide the optimal environment for germination and seedling growth. (Source: hortnews.extension.iastate.edu)


Related Articles