Perlite also considered good. Vermiculite has high nutrient-containing ability. Lower stems as plant matures. Remove lower leaves. Definitely remove suckers.
Tomato flowers are ready for pollination when the petals curve backward.
The window of time for successful pollination is 3 days. Tomato roots do not function at temperatures below 58 degrees Fahrenheit. Water temperature should be 65 to 68 degrees. Relative humidity decreases with temperature increase. Hot water in root area does not have enough oxygen for plant.