How does water pressure change with increasing temperature? With air inside, assuming for simplicity constant volume and ideal gas, its pressure variation from 50F to 212F can be computed from T in K: P2/P1 = T2/T1 = 373.15/283.15 = 1.32. Adding the vapour pressure, at 100C the pressure inside is 1.37 + 1.00 = 2.37 atm. This doesn't consider however the volume variation. Since some liquid water becomes vapour, the volume available for the gases increases and this reduces the air pressure, so the final result would be less than 2.37 atm.
Usually planted in the early fall, cool-season grass seeds prefer daytime temperatures ranging from 60 to 75 F. With this temperature range, the soil itself is usually between 50 and 65 F -- the right environment for germination.ermination Failure. Grass seeds may fail if the temperatures aren't right for the particular type of grass. For example, warm-season grasses planted during a spring cold snap will stay dormant. As they lay in the soil, surrounding weed seeds take over the space and make it harder for the grass to become established.
Seeds germinate when soil temperatures are above 65 degrees F. Sow the grass seed in early spring through late summer, earlier is better. Harmonize with seasonal rains. If you want to get a head start on preparation, consider planting a cover crop in the fall. (See below for more details.) Preparation.