It depends on the type of plant, but in most cases, if you strip the foliage from the lower stem & cover the stem with potting soil, adventitious roots will form along the part of the stem that you just buried. Many actually employ that treatment as a strategy when they are growing tomatoes.

Al

What do you mean by Strategy Al? What does it make them do? Become stronger?

Karen :)

By 'strategy' I meant part of a purposeful plan. If I start with a large tomato plant, I usually strip almost all the bottom leaves & plant it very deep - so only the very top 2-3 sets of leaves are above the soil. If I start with smaller plants, I only fill the container 1/3-1/2 full when I first plant. Then, as the plant grows, I strip the lowest leaves & add more soil until the container is nearly full.

Al

thanks Al, as always.
Yes-as tomato plants that were a bit leggy to begin with I did deep plant them to get a better root system.
I still have 5-6 inches to the top of the container so I think I will add more.
It's been such a wet foggy spell here in NJ the plants look a little "long" again. I might have to wait a little longer for fruit but it's most likely best for the plants in the long run

Our spring has started out the same as last spring. Frosts well past our regular 'last expected frost date' of May 15. We were still getting frosts on Jun 6, and last night was in the low 40s again - NOT good tomato weather, so I feel your pain. ;o) Today starts a warming trend though, so perhaps we're done with the early springlike weather. Fingers crossed.

Al

laura,
2-3 springs ago, this area (in and around NJ) got above average rain, and many tomato growers never got any tomatoes at all, or low yeilds. We did, but we're in Philly, making us a zone 6b, more than a regular 6. Check with family and friends to see how their tomatoes are growing. Again, ours are growing like they're on a mission from God, but we got freaky zoning, due to city heat. (And seaweed fertilizer has increased our yields greatly.)

I just don't want you to feel disappointed, like you can't grow tomatoes, if it's like that year. It's happened before. But, well, if you can, and you know no one else that has, hey, gotta have that inner joy of success, too.

thanks for the words of encouragement. It's still soggy here but there was a bit of sun today. still no fruit set but close inspection shows happy looking flowers some are seriously huge.
Keepin' crossed with a smile with hope for success :)

Flowers mean fruits coming! Cool! And, looks like we might be out of the woods for the will-it-ever-stop-raining season. loll