I start plants too early in my basement under lights because I can not stand winter. If you can repot and keep enough light on your plants so that they don't start declining, I think you do gain time. I don't think it works out start a month earlier and get fruit a month earlier. The reason is a small but healthy plant may adjust to the garden and grow like a weed. A larger plant may be set back more by the hardening off process and be slower to adjust to the garden.

My plants were ready to go in the ground this spring, then it snowed in May which is something I have never seen before. By the time I got may plants in the ground they were declining from being in small pots too long and outgrowing the lights and shading each other. Smaller plants can take delays and you don't feel panicked about a late spring and no room under the lights.

In other words, are there any benefits of starting seeds earlier in order to get earlier crops?

Basic answer, no. Granted it is somewhat debatable but as Helen indicated the plant grows in cycles. A set-back cycle triggered by transplanting an overly large plant can more than off-set any gain you might have had. And the gain, if any, is not a 1;1 (month early start=month early crop).

Instead what many who start their plants extra early in the hopes of getting an earlier DTM find is increased costs, increased stressed plants, increased loss of transplants, and little to no gain.

More effective, studies show, is starting some of the plants a week or two before the optimal time for ideal transplant size, using early and/or cold tolerant varieties, and at the same time improving the growing conditions they are transplanted into - pre-warmed soil, shelter from early spring weather like clothes etc, deeper transplanting, etc.

A combo of the approaches can, if all else cooperates, gain you a couple of weeks.

Dave

How many plants are you talking about? If you aren't a market grower, try some early plants. A month early in the house is easy to do on a metal shelf with shop lights in the basement. Mine were more than a month early due to cabin fever and tomato seed ordering mania.

Please don't discriminate on us market growers b/c many of us do start large numbers of plants much earlier and we expect payback. I haven't been dissapointed in the last 20 years for doing so. Certainly there is a larger investment of time and resources and one should not expect to harvest according to a DTM chart for early planted seeds but many of us market growers show a profit due to season extension sales.

I like 10 week transplants because they can be trench planted and show almost no transplant setback. I'll admit that the past 2 years I just planted 8 week transplants into my heated high tunnels b/c the extra labor of trenching 700-800 plants can be offset by just transplanting younger plants earlier and providing the necessary heat to keep plants growing. I find that the earlier you plant in the ground in high tunnels the less you need to worry about hardening off since the sun is not as damaging in early March as in May or June.

For those same reasons I'm still heating and harvesting from those same plants today, a full 8 months after they were planted.

I'll agree with Helenh that you can not use DTM directly but since I start over 200 varieties I know that all varieties can be successfully started early and their DTM is relative to published values. Keep in mind that not all published DTM values are reliable and that different seed co. will publish widely different values for the same variety.

Sorry if you thought I was discriminating against market growers. What I meant was that nothing is lost by someone trying a new method on a few plants.

I know market growers make more money by extending the season, but they need to know what they are doing. As you described there are many details to be considered.

In my experience, if shortly after plant out you get temperatures in 70(day) 50(night) range or higher, seedling size is not going to make much difference. Say, one seeding is 10 weeks old the other is 5 week old((exact same variety)) the difference in having ripe fruit is NOT going to be 5 weeks, but probably about 2 weeks. A lot of us get satisfaction from that 2 weeks difference too.