One of my plants I grew over the winter by accident. It sprouted in November and I thought it was a different plant (I have lots in my greenhouse) so I just left it.

Turns out it was a Lowryder 2 must have fallen from one of my seed-mothers and into another pot - LOL

Anyway I'm beginning to LST her as she would be well over a foot high by now. I will take a pic soon - keep forgetting.

They can stretch in my experience so keep them as close to the light as you can. If need be early on elevate them so they get as much sun as possible. I found the ones in the areas of my greenhouse that received less light ended up stretching (makes sense) but they were also predominantly males - could be a fluke but who knows?

Males are generally bigger and grow faster but not always - its easy enough to sex them before they drop pollen so don't worry.

They grow fast - I would start them in a big pot if you have room as they root quick. I grew out 10 in 3 different sized pots and it really made a difference to size and growth rate - but for seedlings a small pot is ok of course.

They don't respond to topping very well and I wouldn't recommend it, they are effectively flowering as soon as mature so its not like they are vegging and can get over the shock more easily. They generally form one cola at the top and a few lower ones (4-8).

I'm trying LST as I have this one plant that has technically vegged for 6months which is weird for a Lowryder - of course it could be a White Rhino as I lost a few seeds when I burned myself with a spliff - but that's another story...

Last year I started some Lowryder 1 in May and some Lowryder 2 in July.

I think that this year I started on March 15th with some fresh spouted Lowryder F2's from my seed stock (I had about 250 seeds from one mother ) and they are doing great in the greenhouse.

I would still germ them indoors where you have a stable temp - I lost a few to the frosts we've had at random lately. I tried to germ some in the greenhouse but they more stable indoors tbh.

With a greenhouse like that you should get 4 big mums in there no trouble.

My biggest female reached 29' so about 2 1/2 feet high. 4 feet will be plenty.

I fed them on Bat Guano and used a regular compost with some vermiculite added and some stones in the bottom for better drainage. You will find when it gets very hot and they are getting big they will drink a reasonable amount of water but its better to get some air in the greenhouse rather than just wang more water in

Grow some other plants in with your weed that pests don't like e.g. Chrysanthemum's as lots of pests hate them (pyrethrium is made from them so no wonder) they are small and you can even stick a few in your pots or grow some in small pots scattered about.

Good luck - post some pics when you can