Wisteria Seedlings; when do I repot?

[s2kMark]

I planted purple wisteria that I ordered from Eastern Leaf, and 3/5 sprouted. This is them after about 2 weeks since sprouting:



The tallest one is about four inches tall. They’ve been outside their life, and get good Miami sun during the day.

When should I consider repotting them? They are in pure peat moss right now, by the way. What are the pros and cons of planting them in the ground to encourage strong, rapid growth? Does anyone have a link to a detailed, informative website on identifying the taproot?

 

[Guy Vitale]

Grow them in the ground, you'll get great growth in very minimal time and will encourage flowering much sooner. I'm guessing in Miami you can repot anytime in the cooler season.

 

[Ry2Tree2]

You could move these into the ground early next spring if you want. When developing seedlings in the ground, I don't think there is much negative to speak of. I was advised by my teacher to cut large roots while the tree is in the ground the year before planning to actually dig it up. Also at year 1, I wire the trunks to an interesting shape and thereafter you can do branch selection along the way while in the ground as well.

Regarding the taproot, it's pretty straight forward - it's the root that grows straight down. Chop it back, making sure to leave some fine roots above it. You could also place it through a washer so one day the tap root hurdles itself and radial roots grow immediately above that point. Alternatively, plant the seedlings on a flat tile to encourage a radial spread around the area of the trunk.

 

[s2kMark]

Thanks for the great advice everyone!

I have a few other seeds I’m currently stratifying (black pine, acer maple, cork elm, sweet gum) that I will hopefully get seedling out of soon. Could I use a planter’s box to simulate planting in the ground? I’d like to save my ground space for fruit trees. What soil mix would be best for a planter’s box.

As for getting horizontal root growth, could I use a plastic lid like a piece of tile beneath the roots? I do this with adenia after cutting their roots to get horizontal root growth. If so, can I do this without cutting the taproot? I’m worried about killing the seedlings.

It is Miami, so it is Summer all year long practically. I have the seedlings underneath an overhang that gets strong, direct light for around 6 hours. With the species I mentioned, should I keep them away from full all day sun?

 

[Ry2Tree2]

No idea if a planters box will simulate ground growing. Is that equivalent to a raised bed? Plastic could work, but if you plant enough seedlings, losing a few will be no big deal. I have no idea about those species and Miami climate, but I assume they'll be okay.