Canna 2012

Hiya Kristen.

In one of your earlier posts, you said that they could be sown as late as early Feb, and since 1st of Jan has already passed us by, I thought maybe you meant 1st Feb, my bad I assume though that I could still wait until early Feb?

 

I remember reading on cooltropicals that thay do them mid feb because of light levels in january,so no rush freddy im just over keen and bored

 

Ah, that explains my confusion, thanks for vlarifyingh

Well you are asking someone who is only making an educated guess ....

Delaying to 01-Feb reduces the time that the plants will need to be on a windowsill before better light and warmth arrives, so definitely a good idea.

Flip side is that it reduces the time available to get to flowering size, before the end-of-Summer.

If you sow early, and do not have enough light (and secondly warmth) the seedlings will either die of cold or grow leggy because of lack of light.

Personally I don't think heating the greenhouse helps, the plants need more light than is available in the Winter months.

But light without heat won't help either - the light will be wasted if it is too cold for the plant to grow. (Its possible that Metal Halide is a better choice than tubes in this regard as MH will generate heat, so if used in a greenhouse inside some sort of localised "tunnel" or insulated area then there should be enough heat for plants to grow).

But ... I've come to the conclusion that it is easier and much cheaper to heat a well insulated enclosure, and thus heating a greenhouse is pointless until light levels are good enough, and the only heat needed is for the occasional chilly night - April, or at the very earliest March. So until then I have my grow lights indoors, and I move them to the conservatory in March.

 

No no, not at all, it's more important than that

 

Thanks Kristen, for taking the time to clarify a few things, some very useful info

For your next task you must go on a quest, to find the Holy Grail

 

Just to say, I'll go for the middle ground, and look to sow in a couple of weeks.

 

Hooray! Something easy for a change ...

 

Pretty sure the taller ones will grow faster from the get-go ... however, a bit of legginess may matter less to tall varieties than to shorter ones, in the long run ... so I think starting short-ones earlier in the hope they are less muck-about by low light levels may not be any better than tall ones.

But its only supposition I'm afraid.

 

I always sow mine around late January/early February, after germination, this gives them around 6-8 weeks on my windowsill by which time they are on average 12-24" (depending on variety) by the time they're hardened off to go in the greenhouse in April.

I have got C.altensteinii (a tall variety) flowering by July/August and up to 11ft tall in 7-8 months from sowing (September)

 

Kristen, out of interest (at this stage), what wattage MH lamp would you recommend?

 

When I purchased my general thought process was:

What area does each Wattage bulb cover? Too low a wattage doesn't cover very much.

What would be the price/benefit equation for, say, 2 x 400W rather than 1 x 800W. Clearly 2 x 400W allows running one lamp when you only have a few plants to look after. Generally the contactors (i.e. a relay which is switched by a time clock) will run a couple of devices, but not "lots", so the maximum number of lamps is determined by that - more lamps and you have to buy another contactor.

Cost of bulbs is another factor. They need replacing each season, really, as their light quality drops off markedly over time. CFLs last years, and LEDs "forever".

I went for 400W which (for me) covers 1 Metre square - provided I can organise the plants around the periphery so they get enough, as they are basically only getting light from one side. Its fine for some taller things that are doing only a bit more than tick-over, but around-the-edge would not be so good for plants being brought on actively.

My T5 rig is 60cm square (0.36sq.m), and will cover an area only very slightly larger than itself. It has 8 tubes (24W each, so total = 200 Watts), so its still going to be 400W per sq.m., or maybe a bit more. I plan to use that for seedlings (all same-ish height)