Some people transplant, some people don't. I never transplant and my toms grow just fine.

They do that mainly to save room under their grow light or on their window sill. For example I usually start 15 seeds in a clear plastic container about the size of a shoe box. If I were to start each individual seed in a four inch pot they would take up about two or three times as much room. Also some seeds might not germinate so you would have plantless pots, which take a lot more potting soil or seed starting mixture than would be used for the same seed in a flat. But for large quick growing seeds like squash or cucumbers I put the seed directly into the pot.

Why can't I just start them in a the transplant container like the other seeds?

You can do that too.

Why can't I just start them in a the transplant container like the other seeds?

As other have said you can if you wish and some do since they want to skip the transplanting work. But keep in mind the additional risk of too much soil in the container means too much water for a very young seedling.

They do that mainly to save room under their grow light or on their window sill.

Actually that is only one reason and not applicable to all growers. For professional growers and for many of us it is just the opposite - it allows us to germinate thousands of seeds in just 1 flat, hundreds in one small container. Then they get transplanted to growing containers for the lights or greenhouse.

The primary reason for transplanting, for "potting up", is the benefit to the plant. It triggers a hormonal switch in the plant. The plant switches the type of roots it develops from tap root to fibrous feeder roots and slows top growth at the same time. End result is a plant with a much better developed root structure that is more adaptable to final transplanting to the garden and helps avoid the top-heavy transplants you often see.

If you buy transplants many are surprised to discover that those 6 packs you often buy your plants in weren't where they started. That 6 pack is their 2nd or sometimes even their 3rd transplant.

If you want to read more about "staged transplanting" or "potting-up" a search here should pull up the many previous discussions on it IF the recent server woes here didn't banish them all off to the cosmos.

My suggestion to you is to try some both ways and note the results you get. That way you will know which works best for you.

Dave

I could be wrong here, but the only support I have been able to find for the "fibrous root" theory is a 1927 study, which concluded that the potting up practice did not increase tomato yields. Also I understand that when the tap root hits the bottom of its pot, which it does in a day or two, the same fibrous root development is triggered.

I plant my seeds directly into 3.5" pots, and transplant about a third of them in order to place the best plants in the center of the pots. In 30+ years of doing this I have never noticed that the transplants were different then the direct plants.

If anyone can point me to any scientific studies that show that potting up increases tomato yields, I would love to learn.

TomNJ

Re: the fibrous root development - I don't need studies. I start my tomatoes in clear beer cups, so I can see the development of the roots as I add soil. The roots go right up to the top of the cups. Mine are started in 16 oz. clear cups with lots of holes in the bottoms. I start with about 2"-3" of soil and keep adding as the tomatoes grow. By the time I plant out, the cups are full of hardy roots all the way up --- I don't use any lighting other than sunny south windows and don't have problems with leggy plants.

Tom - AFAIK no one has ever claimed that potting up increases yields. That isn't the focus of any of the studies nor the reason for using staged transplanting. It may be a secondary benefit but that would all depend on the growing conditions, not the potting-up.

The reasons for using staged transplanting is shorter node lengths, stockier, and generally healthier transplants because they have more foliage for photosynthesis and their root systems are balanced to their top growth.

Those plants are less likely to be stressed, more tolerant of stress if it happens, faster and easier to harden-off, quicker to recover from any transplant shock, and make a quicker hormonal switch to production mode.

If proven "increased production" is your only yardstick then the only claim staged transplanting makes is that a healthier plant is more likely to give you increased production IF the growing conditions provided are ideal.

If the growing conditions aren't ideal then the healthier transplant is likely to at least give you more normal production when compared to the poorly developed transplant. ;)

Dave

Thanks Dave. I never noticed these improvements in plant structure and health for my transplants vs direct plants. Perhaps this year I will try some experiments and label the plants for comparison. I wouldn't mind taking the time to pot up if I could expect some tangible benefits.

TomNJ

I pot up to change the growing environment from seed starting to transplanting.
The soil mix is different, the container is changed to a peat pot or cow pot,
and I place the start down an inch below where it was growing in the plastic pot or peat pellet and it is centered and more perfect in the upright.
And YES cut that netting on peat pellets as Dave Digdirt has mentioned.
I do this for my own plants as well as for plants we sell and/or give away.

I grows stuff to sell, albeit on a small time basis (last year I sold about $600 worth of tomatoes, herbs, peppers and a couple types of flowers). All my seeds get sown in a plastic to-go restaurant container. After they germinate and get 2-3" tall, I move them to usually 3" nursery containers. This allows me to make sure every cell is filled as well as bury the stems to the leaves. By the time they are ready for the gar-den, the container is full of roots, the plants are 8-10" tall with several sets of leaves and I don't need hundreds of square feet of room and lights to cover them.

Mike