How long to keep seedlings in seedling tray?

I currently have all my seedlings still in a basic seedling tray with the small chambers. I was wondering when would be an appropriate time to transfer them to their own small pots? Some are currently anywhere from one to two inches tall and have a set of real leaves aside from the cotyledons. Some of them have been dampening off, and I’ve never dealt with so many seedlings before, should I mix a bit of hydrogen peroxide in with the water to deter that from happening?

Thanks for your input,


Hi Max,

I always remove seedlings from the seed starting tray one to two days after they have broken ground. This accomplishes two things, it prevents two seedlings from mingling roots and it allows me to treat each seedling individually.

All my seeds are from Hybrid Tea stock.

I transplant the seedlings into 4" plastic pots with potting soil since the seed starting mix has no actual soil in it.

Hope this helps you…always be careful not to bruise or touch the roots in any way.

damping off is rarely problem here, possibly because seedlings grow in cool (60 deg F) environment; what temp are your seedlings growing in?

Hi Max! I do essentially the same thing as Jack, with a few minor differences. My seed starting tray has about 1.5 inches of pro-mix in it as the base and another 1/2 inch or so of sand that is on top of the seeds. I transplant as soon as the cotyledons have completely opened. I have not had a problem with damping off, but then my sand has been bleached and then rinsed multiple times. I try not to keep to trays too moist, either.


You should be able to transfer these seedlings at any time if these are in individual cells and have their own root space (as I understand from “small chambers”).

If they are with other seeds and seedlings, they should be transplanted to their individual pots as soon as possible unless you have space and sufficient soil/medium to grow them to maturity where they are.

As many others do, I transplant seedlings as soon as I can after the cotyledons emerge, as there is less shock to the seedling that way.


Huh, so I can move a good portion of them now. That’s a lotta pots.

It is rather cool where I am growing them. I’m growing them in my dorm room, actually, one is in the window, and another tray is on my side table. I have sunlamps on them. So far I’ve gotten many nice seedlings, some look like they might want to be climbers (kinda lanky) but that’s probably cause they needed more light before I bought the sunlamps. The yare growing in the individual cells, but they are small and tend to stay too moist, so I’m going to switch them out soon then. for one of them I can still put on the plastic clear top to the “kit” I had, so it has a green house effect, but otherwise, but the other by my window, I don’t have anything tall enough to cover it to create that and still permit light.

Quick question. I have a lot of seedlings I picked from bushes I saw at a house, I’ve labeled them as Carefree Beauty since it still has some pink blooms on the plant whne I picked them and the leaves didn’t look like Knockout, but I’m not sure 100% of the mother plant’s identity. Lots of hips.

Does anyone know what to expect with CB seedlings?

I also have some L83 that were very eager to germinate, and have a few which are very strong growers.

I’m rather excited! Thanks guys.


If you happened to get the RHA newsleter today you’ll find my article about potting media selections. Also implied there is my laziness. I keep seedlings in the same six-paks until after the 1st, or even 2nd bloom. Climbers will get a foot tall and have roots all over the bottom of the tray sometimes. If you discard everything that is boring you won’t find the tray crowded. And with fertilizer, plants will stay happy, unless they get spidermites. You are right-that’s an awful lot of pots, if you put every seedling in its own pot. If you are serious about getting rid of disease-susceptible plants you can probably screen right in the tray by putting them near a disease carrier once its safe to move them outside. Keep only the one or two that can take it.

Several yrs ago, a batch of Carefree Beauty op (probably self) produced seedlings which mostly looked like the parent.

You are fortunate to have some l83 seedlings; l83 is mentioned in the latest RHA Newsletter.