Why do we pot up?

I've been wondering about this. Many of us do it (myself included, when I'm sufficiently motivated), but why? I mean, we sow many seeds directly into the ground, and they grow. They've evolved to grow directly in the ground. So why, when we're starting something from seeds for transplanting, do we step up in stages, rather than just starting in a larger pot, or transplanting directly from the small starter pot to the ground?

That is an interesting question! :)

Growing things in a large pot is not the same as growing them in the ground--containers hold water differently, and if you have a small plant in a large container, the container will hold too much water and it increases your chances of root rot (tapla has a really great thread as a sticky in the container gardening forum that explains water movement in containers much better than I ever could, I definitely recommend checking it out if you haven't read it before). So that's why you pot up one size at a time rather than jumping to a huge pot right away.

As far as not transplanting directly in the ground from a small pot...when people start seeds indoors over the winter, generally they're starting them earlier than they could start them outdoors so that they can get a head start on the season. Those little tiny seedlings don't stand much chance against cold and frost, so you're better off potting them up and then waiting and planting them out in the spring. Or even if you start them indoors at a time when you could have planted them outside, it's stressful to change conditions from inside with consistent temperatures and artificial light to outside with bright sun and hotter or colder temperatures, and it's easier to get seedlings through that adjustment process if you let them get a little bigger.

I have started some in little dixie cups, is that ok? I have only had two that have germinated thus far, and one was growing well, but now looks puny. The others are Brugmansia that haven't done anything, but I think I needed to have read up a lot more on doing those before I started. Thanks for all the information, it is very helpful!

This is an interesting question, I now wonder if the larger containers that I've filled for winter planting are too large.

I am so confused by all that is going on that I haven't even started the Polar Planting! LOL

misty, i haven't planted yet, but I did start filling my pots as they became available so I wouldn't have to do them all at once. I tire out easily. It is really hard to decide what to plant, isn't it, and now I have to wonder about the large pots, like the window boxes.

There is just so much to learn about gardening that it is overwhelming at times! I fear I will end up planting WAY too many and I will be in over my head come Spring! Being new to gardening, I don't want to get in over my head to quickly and be even more lost that I already am. I keep looking at my list of seeds and trying to figure out which ones to do, but there are so many that I love that I just get stumped! LOL

I guess it is very difficult for new gardeners to take in all that we old gardeners do that is classed as second nature once you have been doing it for lots of years, but then you are just like all the old timer who were once like you, had to learn and from scratch, so dont get despondent about it all or you will be put off by all the terminology rather than the skills needed.
Depending on the seeds you are growing and your zone, then you dont have to plant into pots or growing trays, but to do so, gives you an earlier start to the growing season, some annuals dont like root disturbance, so you would sow then directly into the soil come spring, some perennials are better grown in pots or trays so that you then divide them up before placing them into the garden as these are in the earth for many years and would be too overcrowded if seeds were sown directly into the ground and it saves you having to perhaps stand on other plants while you thinned them out by digging the seedlings up after they germinated, so it is really a matter of choice really, some seeds need a bit of heat to get them to germinate, therefore growing them indoors or under cover gives them a bit of winter protection to allow germination.
I do my own seeds by using a 6 inch pot, then use a little pinch of seeds scattered onto the surface of the soil in the pot, some really tiny seeds I dont cover with more soil, others a bit bigger, I use just a pinch of soil to cover them, them I sit the pots of seeds into a tray of water till the soil changes colour (darker) then remove the pots and that is enough water till germination has usually taken place, once the seedlings have 2 sets of true leaves, I use a pencil tip (the pointed end) and lift the seeds out of the soil, holding the seedlings by the leaves, and then place them into flat trays of compost, about 1 1/2 inches apart so the roots have room to grow more, then they are normally watered till it is time to separate the rows of by now good rooted plants and place them into the garden in spring, that is the very basic way of doing it and in time, you will find your own way and a different method after the seedlings have germinated, either seedlings into individual small pots or trays as I do it, I find trays easier to handle, the seedlings get more light and the trays are easier to turn around for light if needed and easier to water also. so give these ways a try and if not good for your needs then find a way you enjoy, I find seedlings easy to handle and the pricking out stage (using pencil or some other stick) very therapeutic in the winter months as I forget all the troubles life throws at you and at the end of the winter as spring starts, you have a good head start for your planting, just dont grow too many of the one kind of seeds or you will have no room for others, seed trays and pots do take up a fair bit of space and then all the watering and general care, be patient and enjoy. A good starting place is your library or book store who have a huge selection of books on seed starting and germination techniques. good luck. WeeNel.

Thanks, all, for your answers to my question! It's just one of those things I've done without really thinking about it, and it's nice to know why I'm doing it! And some things are just different for us down here in the land of (almost) eternal summer, so not everything needs to be done quite in the same way as it would in a more "traditional" gardening climate.

Again, thanks for explaining things to me!

i always thought it was because small plants have a higher mortality rate. so if you had a hundred seeds and 20% didn't make it you wouldn't waste 20 larger pots. but if your confident they will all germinate and make it to the larger size, it makes more sense to plant them in the larger pots to begin with. not to mention the economical side of less potting mix and less water.

That makes sense, too!

Things like sun flower seeds, peas both flowering types and veg types and most large seeds are best planted say 2 seeds to each small pot as they have a large root system very early on after germination, but most others would be planted and scattered in pots or trays so that, a) they germinate better with the company of each other and, b) for the space they take up individually potted as mentioned before, but in each gardeners temp, situation, we all adapt to what suits us best, there are no right and wrong ways, just better ways to care for the plants and their needs, so good luck you lucky gardener for having eternal summer weather and temps. WeeNel.