When to sow greenhouse tomato seeds?

Greenhouse tomato seeds can be sown from mid to late winter, around January to March, when there are still chances of frosts outdoors but temperatures and light slowly start increasing indoors.

Here's a general timeline of when to sow greenhouse tomato seeds:

1. Late January to early February: Start sowing maincrop tomatoes (i.e., varieties that will produce the main harvest in the summer) for growing in large containers in the greenhouse.

2. Mid-February to early March: Sow cordon tomatoes, which are varieties grown on a single stem, suitable for growing in smaller pots or grow bags in the greenhouse.

3. Mid-March to early April: Sow late maincrop tomato varieties for growing in open ground in the greenhouse or for planting outdoors in sheltered locations like a cold frame or under cloches.

4. From late March to April (or later): Sow tomato seeds for outdoor planting and harvesting late in the season.

You can also start sowing earlier if you have a heated greenhouse or grow lights to provide supplemental lighting. This can allow you to get an even earlier harvest.

The specific timing of sowing greenhouse tomato seeds may vary based on factors like your local climate, greenhouse type, and the desired maturity time of the tomato variety. It's always a good idea to check the seed packet instructions or consult with experienced gardeners or growers in your area for the best advice.