Mayo62 said:
I will have to measure my pots so I'll know which size to order
A #1 pot is a 1 gallon pot, right? How high are the ones you use?

You say that you put the seedlings in a #5 can in August ...Are they a year old by then, or did you sprout them in that same Spring?

Hello, Mayo.

Sorry to be so late in replying, I lost track of this thread. Yes, as far as I know, a #1 is the same as a 1-gallon (or, it started out that way). Unfortunately, everything is being downsized as time goes on, and the newer #1 pots are not quite as large as the 1-gallon pots made 15 years ago. That's probably part of the reason for the name change, since #1 can be anything you want, but "gallon" is an actual measure of volume.

A typical #1 pot is about 16 cm tall and 15 cm wide. Sometimes you can find taller pots - I recommend them.

I sprout some of my earliest harvested seeds in August and September, after 3-4 weeks of moist refrigeration. I usually start them in 9 cm square pots, with up to 9 or 10 in a pot. The next spring, or, as soon as the fans measure 3-4 mm at their bases, they can be moved into 1-gallon pots (or field-planted). They really appreciate the extra root room, and will put on size rapidly. They can stay in the gallon pots until it's time to line out in beds or move them into the 5-gallon pots. If you have the time, and you're itching for something to do, you can do an intermediate step into 2-gallon pots. This is fast and easy, and gives the roots new soil to grow into. Containers are convenient, but the thing to keep in mind is that once a root hits the side of a container and starts to grow around it, it's really just half of a root, since one side of it is running against plastic. This slows growth markedly.

Usually, those late-summer/fall sprouted plants are big enough for the 5-gallon container by the next August, which would make them about a year old.

When I ran a lot of seedlings, I thought daylilies needed much more stratification, so I would wet-refrigerate around October, and sow around March. By then the root initial was already peeking out of most of the seeds, which, I felt, made them easy to plant. With good conditions, (steady, light fertilization and lots of sun - along with a bit of standing water in trays) those seedlings would be at least 5 mm at the bases by July, with roots bulging the 9 cm pots, and I'd line the strongest of each cross out into rows. The runts never seemed to amount to much, so I tossed them. They'd grow steadily throughout the summer, and put on quite a bit of size with the fall growth spurt. A good percentage of them would bloom the following summer.

I wouldn't worry about your winters damaging seedlings planted through August, unless there's something very unusual about Zone 9a in the Netherlands. If you're concerned about frost, a simple overhead cover should get them through anything your winter might offer. I've used clear fiberglass sheets, clear plastic film, and white woven frost fabric before. Always try to remove it during the day, so that the plants get maximum light.

Ken
East S.F. Bay Area
USDA Zone 9 - mediterranean

Mayo62 said:
you said
"A month or two after sprouting, when the seedlings are around 12 cm tall" ..
How do you measure that? From the ground to the tip of the longest leaf?
Or from the ground to the point where the leafs are bowing down, or..?

Some of my seedlings that I put in a seedtray on 26th of July are already more that 20cm from ground to tip of the longest leaf...
(They were germinated about 12 days before that in a ziplock baggy with perlite, water and some hydrogen peroxide)

Should I already put them in a bigger pot??

Hi Mayo,

I don't actually measure their height , I just look at how the seedlings are bulking up.

I can't see how large those cells are, but those look like well-grown seedlings. Ordinarily, you could wait a bit more before transplanting, but since winter is coming, keep in mind that the added soil mass in a 1-gallon pot will provide a lot more temperature stability through the winter.

Ken
East S.F. Bay Area
USDA Zone 9 - mediterranean

Commercial nursery pots are numbered as 1200, 300, 600 etc. here. I use 600 which is about 2 gallons for potting two fans of a registered daylily. A friend of mine uses 300s to pot baby seedlings
http://www.greenhousemegastore...
http://www.greenhousemegastore...

I remove the seedlings from the trays at about 5 weeks old, they should have there third leaf and a few roots coming out the bottom of the tray. Looks like you are using large trays(36-48 hole, I use a 72 hole) so they could stay in a little longer.

I also like early sun rather than late, the sun seems to help the daylily open better and faster.

hi Ken and Fred ( @CaliFlowers and @Spunky1 )!

thank you very much for your info
It is great to hear how experienced growers like you do things, that gives me the confidence that I need

I have bought square pots that are 16 x 16 x 23cm and am in the process of potting up my seedlings
When they were around 4 weeks old they were 4-5 mm at the base, so I didn't want to wait any longer.

Yes, I have 45-hole seedtrays and they are 11cm high, so perhaps I could have waited longer potting them up.
But now I can take my time doing it and don't feel that I have to rush it

I can see that it does them good, though! The ones that I potted up 5 days ago are already a lot bigger!
I díd however put 2 to 3 seedlings of the same cross in 1 pot... Shouldn't I have done that..?
I can re-pot them to bigger containers this winter, as long as it isn't freezing, right?

Yes, I already bought big rolls of that white woven winter fabric
The pots with the seedlings will be on my veranda all winter, so they are protected more than in the garden itself already

Thank you again for all your help, you make ATP the great place it is!


Mayo