Tomatoes
Propagation is mainly from seed. Can also be propagated from cuttings (suckers). Seeds sprout in 7–14 days, can be repotted after the first set of true leaves emerge. Move to its final container at around 8 weeks.
Tomato seedlings need light and air movement to develop well. Lack of light will create leggy seedlings, and lack of wind makes stem thin and weak. You can use a fan to provide the latter.
Tomato seedlings should be hardened off 1-2 weeks before planting outside, by gradually exposing them to outdoor temperature, direct sunlight and wind.
When transplanting, the stem can be buried up to the first set of leaves and it will form roots along the stem. When planting outdoors, the stem can be buried vertically or horizontally in a trench. Burying the stem can help leggy seedlings regain a stronger shape.
Tomato varieties can be determinate (grow to a more or less fixed size, with a fixed amount of fruit), indeterminate (grow and produce fruit throughout the season), or somewhere in between.
Determinate varieties are better left unpruned, as cutting growth can potentially limit the amount of fruit. Indeterminate varieties should be pruned, e.g. the suckers (secondary stems) growing at 45° between the main stem and a branch. This cutting can optionally be propagated in water to create a clone of the tomato plant.
Varieties can be heirloom or hybrids obtained from cross-polination. When tomato varieties cross-pollinate, they produce fruit true to the host plant, but the seeds will be hybridized.
You can help pollination by tapping on tomato flowers. Cross-pollination can be prevented by planting the different tomato varieties in separate places, or by using nets.
Tomatoes require temperatures consistently over 10°C to thrive. Prolonged exposure to temperatures below 10°C will damage the plant and below-zero temperatures will kill it. The cold damage can translate to stunted growth, fewer or poorer-quality fruits.
Tomatoes require ample space. Containers should be at least 20L per plant. In the garden 70-80cm between plants to encourage airflow and access to sun for best productivity.
Companion plants for tomatoes: basil, mint (in pots), marigolds.