Heat is essential for growing plants from seed to harvest. Not only heat, but also an also consistent temperature not exceeding 5 degrees from the suggested growing temperature is a key element in crop production. During day and night because of light and earthly elements cause the air temperature to fluctuate resulting in plant stress. Plant stress from temperature begins at the seed starting stage. Spinach for instance is greatly affected by hot, inconsistent temperatures. Spinach prefers cooler temperatures below 80* Fahrenheit. Under propagation lights, these consistent temperatures can be difficult to maintain for the proper amount of time until successful germination. The mat warms the rooting area by as much as 10-20 degrees warmer than the overall temperature, and it raises the soil temperature to about 85-90 degrees Fahrenheit.

Creating a greenhouse effect, and providing insulation and protection to plants from dehydration can be as simple as placing a humidity dome over the seedlings, or small plants. Even larger plants generally prefer the added protection of a plastic cover depending on the temperatures outside. Inside, seed starting can be greatly improved using a 7-inch propagation humidity dome (under $7) and an economical propagation tray. Actually, even doubling the propagation tray, which provides stability, and stacking the humidity dome on top of each other improves insulation, which also decreases the chances of temperature flux. This means consistent temperatures, and consistent germination. The Perma-Nest plant trays are a heavy-duty tray, providing stability without stacking others, and its increased density provides more root-zone insulation. 

Perma-Nest Plant Trays - SUPER HEAVY DUTY Greenhouse Trays

If you're still having germination problems, or want to improve on your traditional method, you could try out an electric heating mat. The Germination station comes with a waterproof heat mat, and a 2-inch humidity dome that encloses an 11'' x 22'' watertight base tray that can holds a 72-cell seedling insert.

Another option is a typical tray seedling heat mats, they range from $32-$80, with an option to use a digital temperature controller for your heat mat that uses a thermostat to maintain the consistent temperatures required for a 99% germination rate. The Agritape Heater is applied under seedlings and is made of a sheet of polyester that is covered with a resistive-conductive ink. On the sides are flat copper conductors, which power the heater, and then another sheet of polyester is coated over the top of everything to seal the Agritape.

For germination that is even more consistent and improved growth, the Agritape Precision heat mats offer season extension for the small commercial grower, or home gardener. With the adjustable dial thermostat, the sensors included in this model shut off in case of water leakage. It is more efficient providing an adjustable thermostat that includes a temperature sensor bulb to insert into the soil to adjust to fluctuations for precisely the correct consistent temperature for adequate germination.

A cheaper route to prevent soil temperatures from falling below 74 degrees are the Gro-Quick electric soil warming cable. This heating element, a wire with a thermostat, provides warmth indoors and outside. Varying in sizes from 6foot to 48 feet provides enough accommodation for larger plant areas, and even soil propagation trays.

Of course, the ultimate way to start seeds inside is beneath a CFL, or T-5 light setup. Hydro farms Jump Start light system includes a 28-watt AgroBrite full-spectrum fluorescent tube. A combination of the lighting systems, and heating mats with a thermostat, can provide for almost carefree germination. Minimal time, besides checking for water will have seed started within a couple weeks, ready to be transplanted.