Are you growing short season tomatoes? The days to maturity on the seed packet starts counting on the day you plant that tomato in your garden. If you choose a tomato that is mature in 100 days and plant it on June 1, you can expect your first ripe tomato sometime in September.
Plant several varieties. Then if one type fails to thrive, you have back-up. Tomatoes perform differently from year to year - the one that failed last year may be great this year. But if you grow a specific one for a couple years and it never produces well, move on to something else.
Tomatoes that produce smaller fruits take less time. I look for types that mature in 65 days or so and grow at least 6 varieties.
Burying the stem doesn't slow down production but it does make for a healthier and more vigorous plant capable of higher production.
Daisy