Um, when a vegetable outgrows its container, transplanting to a larger container is always a benefit. I've never seen a vegetable that didn't like that. One can instead ask what vegetables don't like direct seeding. I can think of a few.

Anything that is normally planted in the garden as a transplant (rather than direct seeded) benefits from staged transplanting. It's a trigger for root development and increased root development equals healthier plants. Commercially grown transplants are often transplanted 3x before they get to the sale containers.

Tomatoes for example are commonly stated in small plug flats or 1" soil blocks and then moved up in container size until they reach the 4/6 pack containers or 4" pots.

But root development triggering is not the only reason for starting small and then potting up. It also also helps eliminate root rot, over-watering issues, perched water table issues that develop in larger containers, etc.

Just do a search here for terms like 'potting up' discussions. There are many of them.

'Potting up' generally does not apply to root vegetables such as carrots and other common vegetables that are best direct seeded such as melons, squash, corn, beans, etc.

Dave

Dave, we've mildly disagreed on this before, but I grow melon and squash seedlings in small containers routinely, with success after plant-out. It's a good strategy with cutworms about, because you can see what you need to protect. It is true, these plants have roots that are practically busting the container you're transplanting them out of, but they seem to do fine. Certainly transplanting makes no sense for root crops, and other crops that ought to be planted relatively densely, like corn, and legumes. But another advantage of transplanting is that you can get a few weeks earlier start on your season if you do your seedlings in containers.

I think of multiple transplantings as a particular benefit for those plants that will grow roots along their stems. You can sink them more each time. That's why I always start tomatoes in a flat and repot into solo cups before planting-out time. I will probably get some hate for this, but I think that this is a good reason to start cucurbits indoors (though they don't need potting-up). You can sink the transplants nice and deep, so they grow a bunch of deep roots to pull up cool water from deep soil once it gets hot and they start doing that tragic afternoon droop no matter how much you water.

Are you just wondering about starting seeds early and transplanting them, or also other kinds of transplants? Garlic, bunching onions, and such can benefit by dividing and transplanting, when they multiply. Jerusalem artichokes are said to do better if you dig them up and transplant them somewhere else when they've used up the nutrients in the soil that make for desirable tubers.

As for starting seeds indoors (or such) early, and then transplanting them, not everyone agrees which plants benefits the most from this. I've personally found a lot of benefit starting peppers, muskmelons, watermelons, okra, tomatoes, and such early, and then transplanting. However, a lot of people might scratch okra and watermelon from that list (particularly if they live in the southeastern USA). I don't know of anyone who direct-seeds peppers, however (although I did try it last year—but the plants didn't get very big, and they didn't produce).

Some things I start early simply to help ensure germination.

There are some plants that absolutely hate any kind of root disturbance, taproot plants like artichokes, beets, and carrots for instance.

There are climates with cool summers, such as mine, where corn, squash and beans are all routinely transplanted and do fine. If we waited for the soil to be warm enough for such plants to germinate outdoors we'd have a much smaller yield. Beans, for example can be sown indoors in March and then again outdoors in May at the same time as the indoor ones are being planted out. That method extends the season by three or four weeks. Artichokes also transplant well.

Of course if direct sowing works in one's climate that is the easiest route. I was just pointing out that transplanting does work for these crops. I often see statements that you 'can't' transplant squash etc. And it's just not accurate information.

Agreed. See above.

I have transplanted corn, maybe2-3 dozen, for an early harvest. Which did work well. Certainly if your in a cold climate transplanting does have its benefits, some which I think comes from cabin fever from being cooped up for months.

What I have seen in my garden is those plants which tend to volunteer (like tomatoes), if you can leave them where they sprout, tend to need less care, less watering, are more disease resistant, and pull thru the dry spells (w/o watering) much better.

I have also had less splitting of the tomatoes on the volunteers, which says a lot.

I tend to think that is because the roots have grown much deeper and are more established than transplants. While these volunteers will sprout much later in the season they will catch up to transplants.

So if you have a plant that sprouts on its own and you can leave it where it is - just give it a chance... Tomatoes grow like weeds in my garden <smile>

Deeper roots on volunteers? Volunteers come from rogue seeds that managed to be buried. Same with transplants, except for those, you do the burying. Volunteers aren't coming up from established root systems, at least for tomatoes. I get volunteers in my compost pile all the time, and they sure don't come from established root systems.

But that's interesting about less splitting in volunteers. Not clear why that should be. If you had several varieties the last year, the volunteers may be hybrids.

I would think that tomatoes from volunteers might split less because they probably have smaller fruits.

I do transplant tomatoes, peppers, eggplant, onions, broccoli, cauliflower, cabbage, watermelons, cantaloupe, sweetpotatoes, and cockscomb

A lot of stories about transplanting come from the time of my youth. There were no fancy containers, no planting trays no store bought planting medium. Transplants were bare root plants set in with a dibble ( If you doing it on a limited acreage) or drawn transplanter if you were doing a lot. In each case each plant got about a pint of water when set. Only brassicas, tomatoes, peppers, sweet potatoes

Today an infinite array of products are available which enable one to transplant almost any vegetable in a root ball. Most of these can use pressed cubes or special paper cups. It is still labor intensive, so is best used when there is a decided advantage. https://www.machines4u.com.au/view/advert/Semiautomatic-Vegetable-Transplanter/172169/

It wasn't my intent to re-start the debate on what should be direct seeded and what should be grown as transplants. It works both ways, if necessary, for some crops in some climates, and for some reasons.

The question was which plants would benefit from staged transplanting, to 'potting-up', prior to going to the garden. And that process, as I said, does not normally apply to the crops I listed. You may choose to start squash and corn and melons etc. indoors and then transplant them to the garden - your choice, fine. But they will not benefit from 'potting-up'. Indeed it may be detrimental to them in some cases.

Dave

@gumby

Splitting seems less common from seeds I save than their parents grown from store-bought seeds (not just with tomatoes, but other kinds of fruit, too: e.g. watermelon). I imagine the reason is similar to the reason you perceived it happening with volunteers. I don't know the answer, but I tend to attribute such things to acclimatization to soil, watering, pests, diseases—also, seed health is probably a factor, as is the overwintering (I've found significant differences in growth between seeds frozen in a fruit and those that weren't, for Morelle De Balbis, a close relative of the tomato), and the weaker seeds might not survive the winter. I think the year plays a big role in splitting, too. Some years, plants behave differently.

I have definitely noticed that volunteer tomatoes and tomatillos are more drought-tolerant than transplants. Things like blossom end rot seem less common, too (considering my volunteer tomato that appeared to be Green Pear, and a Green Pear transplant, which I grew, last year). However, when I started to water such a drought-tolerant volunteer tomatillo, it was no longer drought-tolerant after that.

I've noticed similar drought-tolerance in some transplants, however. I think it was partially due to how I watered, and maybe partially due to the wood ash in the soil.

I tend to think if you treat the plants right, they can adapt to being both drought-tolerant and drought-susceptible whether they're transplants or volunteers. What that treatment is remains to be seen, but how you water seems to be part of the treatment.

Dave, I tend to agree that potting up is not the best practice, since it's just another opportunity to damage the roots. However, there are reasons some people like to do it.

Some people tend to think having too small of a plant in too large of a pot can lead to some issues with soil and/or watering or something (which may be true in some cases, but I think getting the right shape of container, with the right kind of drainage and ventilation, with the right kind of soil can overcome that issue). Or, planting more seeds to help the soil structure could probably solve it, too (and thin later).

Another reason may be that the initial pot just has seed-starting mix, and the plant might be ready for a richer soil long before the transplant. You could give it fertilizer, but some people probably don't have an ideal fertilizer, and just don't want to worry about everything they'd need to give them, due to experiences with one deficiency after another, after treating each one. For people who have had that issue before, I recommend just giving them a little wood ash, and also some nitrogen if necessary. Indoor vegetable and herb plants seem to love a little wood ash, and it seems to help them tolerate containers that are too small a lot better. It seems to make them a lot more pest-resistant, too (more so than just potassium sulfate and rockdust, although that does help to a degree). Anyway, it should have a wide array of trace minerals (which were at one time absorbed by a plant, however changed the structure of some of the minerals may be from the fire) to take care of any odd deficiencies, and it also has carbon, potassium and phosphorus (as well as a lot of calcium)—but it contains no nitrogen. Too bad I didn't try it before I switched to my greenhouse for seed-starting (I saw it as an outdoor soil amendment, but it's great for indoors). Just be careful about soil pH with it, since it's high in calcium. That's why I suggested using a little.

Anyway, not everyone likes wood ash, but I like to rave about it.

<I would think that tomatoes from volunteers might split less because they probably have smaller fruits.>

Not sure you can get smaller than cherry and/or grape tomatoes. Which is why I think it is better root development. That coupled with the fact they sustain drought periods much better and as pointed out are less prone to blossom end rot which is an irregular watering problem.

Give it a try for yourself before shooting it out of the sky. After all the forest is full of trees that do survive (quite well) on their own without being transplanted.

Maybe the short growing period is deceiving to some.

Volunteer tomato plants that are left to grow where they sprout are more taprooted than their deliberately planted counterparts. In the latter case the plants have been transplanted, usually a couple times a the least, before being planted into the garden. Which results in a more fibrous root system. This is almost certainly the reason others are reporting that volunteer tomatoes are more drought resistant, resist cracking better, and have less noticeable problems with blossom end rot. Volunteer roots travel deeper into the soil where soil moisture is more consistent.

Rodney

OK, so that's saying that direct seeded plants have deeper root systems than transplanted ones. Makes some sense. Volunteers are certainly direct seeded. But it has nothing to with whether they volunteered themselves.

I once bought a carrot 4 pack to transplant just to see what would happen, was cheaper to fill up the flat. When I pulled the carrots they were so funny how messed up they were, they were artistic. One had even grown itself into a knot.

<Volunteers are certainly direct seeded. But it has nothing to with whether they volunteered themselves.> I wasn't saying that - not sure anyone was.

@noki33 - carrots needs loose soil w/o any obstructions. I made a box once from a pallet so it was narrow (~3") but about 16" deep. The original idea was just to get it up off the ground so the slugs didn't eat the seeds as soon as they germinated - just to give them a chance to grow.

Added sand and screened everything that went in so it was stone & pebble free. This resulted in straight carrots some 12" long and very sweet. It takes all season in CT but the wonderful thing about carrots is you can certainly harvest carrots anytime.

To be clear: it's likely obstructions in the soil caused your carrots to take a 'detour'. Of course depending on how mature the carrots were when transplanted the detours could have taken place in the pots long before transplanting.

That's true. You were referring to "those plants that tend to volunteer". But again, deeper roots are not about being a volunteer, but about being direct seeded. The former happens to be the latter, but you can have the later without the former. Just trying to clarify.

When people use terms like former and latter things are clear as mud.

It's okay, gumby. I think daninthedirt has a point. Direct-seeding in any form could probably result in a deeper taproot. However, that doesn't necessarily mean that there aren't benefits to volunteers besides that, and it doesn't necessarily mean that volunteers don't have deeper taproots than those you direct-seed manually.

Personally, I'm not sure that the taproot is the reason for the results at all, if the depth of the root is the reason. I've planted tomatoes extremely deep (~5 feet), very deep (~2-3 feet), and kind of deep (~1 to 1.5 feet), and normally, and I didn't notice a whole lot of difference between them other than that the deeper ones seemed to grow more slowly at first, but seemed to have late season advantages. The soil is colder lower down, which might explain why growth was slowed. Potassium is probably more available lower down, due to the cold, and other factors.

Anyway, my conclusion was that I think tomatoes grow roots as deeply as they need them anyway, although you might be able to come out with some interesting ways of utilizing the depth. It certainly should allow the plants more water. I wasn't paying attention to things like splitting for the experiment, but I guess the deepest ones didn't split (I'm not sure if they were prone to it, though). Some of the 'kind of deep' ones cracked, but they were different varieties. I had splitting (only when picked) on a certain cherry that I must have planted at least kind of deep.

The same experiment in a less compact soil might have vastly different results, and warmer temperatures than mine were lower down.

<Direct-seeding in any form could probably result in a deeper taproot.>

That was exactly my point. Allowing roots to grow unimpeded does have many benefits. Said another way - the latter has benefits the former does not.

This is all very sensible. I just didn't want to get deflected here by the premise of "volunteers". It is directly relevant to the question of the OP, which is whether transplanting is bad. To the extent that root spreading gets inhibited by starting plants in containers, I guess it is. But for me at least the advantages of transplantation seriously outweigh those of direct seeding.

I am asking about starting seeds then transplanting them.

It is your garden and you can do just as you wish. IMO there are no rules just guidelines - do as you wish for sure.

"I am asking about starting seeds then transplanting them."

Exactly - the rest of the discussions are tangents. Commonly grown plants that benefit from staged transplanting - tomatoes, peppers, eggplant, some leafy greens like kale and chard, broccoli, and cauliflower.

I am NOT saying others cannot be transplanted but that there are no benefits to them in terms of root development and that there may be some risk.

Dave

"I am asking about starting seeds then transplanting them."

That's what this discussion was about, and several people have noted that root systems might be compromised in doing transplantation, compared with direct seeding. But, as I said, for me, the advantages of transplantation FAR outweigh the possible disadvantages. In direct answer to your question, no, transplanting is not "bad". But there are advantages and disadvantages.

For me, the advantages of transplantation over direct seeding are

(1) increased length of growing season by starting indoors

(2) stronger plants are able to better withstand outdoor conditions

(3) cutworm avoidance is easier if you have a real plant to protect

(4) for small seeds, which make small germinating plants, starting soil is always better than outdoor soil (which has rocks and dirt clods)

Dan I still think you aren't understanding the OP question. It is not about transplanting to the garden. It is about the benefits of transplanting seedlings into increasingly larger containers - staged transplanting - while they are still seedlings and not ready for the garden. Granted that wasn't totally clear as he doesn't know the terminology but this is a continuation of a previous post by the OP where he asked about just starting his tomato seed in an 8" pot and why was that a problem.

For example, we are talking about maybe starting tomato seeds in plugs, then into 2" cells, then into 4" pot etc. All of this done long before they go to the garden. So he is asking what plants can benefit from that process.

It has nothing to do with starting squash or melons etc. indoors and then planting them in the garden rather than direct seeding them. That is a personal choice.

Dave

Yes, Dave, on re-reading the OP, that's probably right. Thanks for the correction. The phrase "transplanting is bad" is what caught my attention. Whether you transplant to larger pots is, in my mind, a matter of whether they've outgrown the smaller pots. If they have, and you're not ready to plant out because of weather, then it's a schedule problem, not a transplant problem.

If on the other hand, the issue is, how large does a plant have to be in order to plant out, that's an entirely different one. I guess I'd have to say that if you want to plant out when a plant is getting too big for an 8-inch pot, why in the world did you start them in smaller pots?

FWIW, I never ever transplant from pot to pot. When my plants are too big for their seedling containers, out they go!

Thanks guys! New info I would not have known.