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.
Several distinct advantages make fall the best time to plant cool-season grass seed. In early autumn, the soil is still warm from months of summer sun. This combination of warm soil, moderate day temperatures and cool evenings encourages fast germination and establishment of newly sown cool-season grass seed. Cool-season grass seed germinates best when soil temperatures are between 50 and 65 degrees Fahrenheit. This roughly corresponds to daytime air temperatures in the 60 F to 75 F range. An inexpensive soil thermometer, available at most garden stores, can help eliminate the guesswork.