As the “I’m starting my tomato seeds” posts start showing up on social media more often, the thought will suddenly hit: “Should I be starting my tomato seeds now?” The answer for most of us is no. In general, six to eight weeks is the optimal time to go from seed to sturdy transplant ready for the garden—unless you have the extra space to transplant into larger containers, like the one-gallon kind. Otherwise, your transplants could suffer waiting for extra weeks to be planted out, becoming leggy, collecting bugs, and taking up a lot of time and space.

To find out when the best time is to plant your tomato seeds, first, find out the average last frost date for your area and count backward six to eight weeks. But remember: The average last frost date is just that, an average, and not set in stone. Spring can be a crazy time for weather, and while you hope and plan to plant your tomatoes two months in advance, Mother Nature may have a different plan. Also, the average last frost date is usually the earliest time to consider planting a tomato plant in an outdoor, unprotected garden. If the frost has just ended, it’s likely there will still be nights in the 30s. This is less than optimal, and some varieties will react differently than others.

This is one of the many reasons I do not recommend planting all your tomato plants at the same time, especially on the early edge of planting time. It’s always possible that weather can destroy an early planting, or the plants can be stunted by bad growing conditions. This can wipe out everything you have. Spreading out your planting can also spread out some of your risk, your work, and your harvest. Depending on your climate and the length of your growing season, tomato planting can be spread over weeks or even months. In some areas here in Northern California, you can plant tomatoes outside, unprotected, from mid-March to early July with positive results.

One possible planting scenario I like to recommend is this:
EARLY SEASON PLANTING: 25 percent of total tomato space
MID-SEASON PLANTING: 50 percent of total tomato space
LATE-SEASON PLANTING: 25 percent of total tomato space
Again, this can be spread over weeks or even months depending on where you live.

Early season planting

Early planting is usually worth the effort because it yields the first tomatoes of the season. Being the first in your neighborhood to pick ripe tomatoes is a bonus. The varieties that I select for the early planting are typically known for producing early, usually yielding large production dependably, and being aggressive growers. These plants are often tested by a wide range of elements; having late, picky, low-bearing varieties won’t help in this stage.

Mid-season planting (AKA prime-time planting)

Prime-time planting is when you plant your best all-around selection. These are typically planted out a couple of weeks after your last frost date. At this time, your soil is warming up nicely and the days are noticeably longer, so this planting has the best chance to thrive.

Late-season planting

This planting sometimes struggles and sometimes thrives, but it usually adds a nice bonus harvest when some of your main harvests is winding down. This planting also excels when you get warm and dry fall weather, extending your harvest late into the season.

I hope these tips help when you start your tomato seeds. Good luck growing.