Soil Temperature and Seed Germination

A few days ago we sowed the tomato seeds for this season's market and home garden. It never ceases to amaze me what little indoor space you need to rear thousands of seedlings. We use two 50 cm x 30 cm x 15 cm trays to germinate approx 150 seedlings from 10 cultivars. When they get bigger we move them into two 1.3 x 8 m beds covered with polythene to rear them before they take their permanent positions in the gardens in early - mid April. Many of the plants we grow I prefer to sow directly outside and one of the most important things to consider when sowing is that the temperature of the soil is high enough for the seed to germinate. Other important considerations include: whether the seed requires any pre-treatment before it will germinate, i.e stratification and scarification (mainly relevant for perennial plants particularly trees and shrubs). how deep you sow the seed - too shallow is better than too deep. that the correct moisture levels are kept constant during the germinati...