Window sill grow

Okay I'm a total newb.

I looked into grow tents, etc. but I really don't have the space. So window sill it is.
Planted three seeds today, using a heated propagator and paper pots with a mix of compost, moss peat and vermiculite. The seeds are Royal Queen "Quick One".

Just waiting for germination and hopefully seedlings to appear in the next few days. I have bigger pots, liquid feed and more soil for later on. Planning to supplement sunlight (which is about 11 hours at the moment) in the evenings with a daylight LED bulb for the seedlings, then add extra lamps once they reach vegetative stage.

This is a low budget experiment, not trying for super pro yields. In Scotland so direct sunlight can be scarce at times, but window south facing so the plants will get what there is.

Will update this with pics of the different stages if germination is successful.

How are you going to flower them and give light and 100% darkness

But either way,good luck

BobThe420Builder said:

How are you going to flower them and give light and 100% darkness

But either way,good luck

Click to expand...

They are autos
They will be fine.

bleedintears said:

They are autos
They will be fine.

Click to expand...

That info does help a lot

Yes they are autoflowers. The extra light will be used to top up sunlight to approximation of an 18/6 light/dark schedule. Maybe there will be a bit of light pollution from street lamps in the area overnight, but not much. By the end of April natural daylight will be 16 hours per day.

Main concern is spindly tall plants, if the seeds germinate successfully. Hence why I will try to top up natural light a bit.

Oh thanks for the support, folks. I'll post again if/when I have seedlings.

The first wee seedling sprouted today. I carefully eased the seed shell from one of the leaves. This seed was closer to the surface than the other two, neither of which are visible as seedlings yet.

Second wee seedling has sprouted from its soil. First seedling from yesterday is growing quite fast. No sign of a third one yet. Well two out of three ain't bad. Sun is out today so looking good. Top up lighting in the evening seems to be doing the trick too, seedling turned towards the lamp.

Things that seem to have worked so far include using a heated propagator. Might have been the key to successful germination on a Scottish window sill in early March. Also good to see quick growth in yesterday's seedling, the soil mix is holding enough moisture without being too wet. One thing I'll do differently next time is to make sure the seeds are only covered in a few millimetres of soil. I think I planted them too deep this time, and had to go digging for the second one. Dunno if the third seed is going to germinate, still no sign.

End of day four, seedlings one and two.

Seedling three appeared today, so all the seeds germinated despite some inept planting on my part. Rescued the situation in time by bringing seeds/seedlings closer to the surface. If they all survive, I will have quite a full window sill in a few weeks' time!

Crow River said:

with a daylight LED bulb for the seedlings

Click to expand...

I've measured the light footprint of a couple of different household bulbs. How large lamp are you using (wattage & lumen)?
Here's how a typical 1500lm bulb performs without a reflector, at a couple of different distances.
PS. all distances are from the white rim on the bulb and not the end of the dome.


Here are some basic recommendations of PPFD for different stages, for context:
Clones/Cuttings: 50-100
Seedlings: 100-200
Early veg: 200-300
Late veg: 300-400
Early flowering: 400-600
Late flowering: 600-900

Thanks for the info. Really detailed!

It's just a daylight (6000K "cool white") bulb I took from a domestic light fitting after I swapped them for "warm white" ones. 12W draw, not sure on the lumens as I threw out the box a while ago just checked the bulb and it's rated at 1000 lumens. I have this in an angle poise desk lamp (so there is a reflector shade) and after the sun sets place the bulb quite close to the seedlings, right on top of the clear lid of the propagator, so maybe 7 cm away using your measurement system, but with a barrier of clear acrylic in-between. It stays on until midnight to give an extra six hours of light approximately.

For additional lighting later in the grow I have an 18W "daylight" (6500K) ceiling/wall mount circular LED array which again I pulled from a domestic setup to install "warm light" replacement. It's rated approximately 1500 lumens but is 35cm in diameter and gives a much more even spread of light than the ordinary bulb. Subjectively appears to be quite a lot brighter too. I've removed the translucent shade so the plants will just get light from the bare LEDs.

So if I use these lights during vegetative stage I should keep them quite close if I read your information correctly? I've also heard that a "warm white" bulb might be more effective during the flowering phase?

All bearing in mind these lights are just being used to extend the "daylight" hours rather than continuously. While the sun is up, the plants are just receiving natural sunlight through the window. Once I'm into vegetative phase I'll be using a foil reflector behind the plants after dark, to help get a bit of light on the window side of the plants, and stop them casting a shadow onto the window that would be visible to any passers-by.

P.S.:- This is very much a budget grow just using some lamps I had lying around, so I'm not aiming at pro yields at all. Really useful information though, will come in handy as this experiment progresses.

Quick grow update on the three seedlings as the sun starts to set on day five. (Photos were taken earlier this afternoon).

As you can see, the third seedling is stuck in its seed case. I tried very gently to free it, but no luck. I have misted the seed case in the hope it will soften a bit and the wee plant can break free.

Day six, towards late afternoon. Managed to prise the seed case off the last seedling.

So far so good. Now I need to think ahead to vegetative stage, placing in larger pots, extra lighting, etc. Before they get too spindly I am going to build a small grow cabinet and put two of the plants in there prior to flowering. This is mainly to reduce odour and the potential of unwanted attention from neighbours, postal workers, etc.

If the third seedling makes it I will keep on the window sill as a control for this experiment, see what happens...

Day nine*, the seedlings are soaking up some gorgeous sunlight. Still in the propagator for now, but on a sunny day I switch the heating off and take the dome off too. Planning on transferring these to their final pots soon: will be 3 litre pots to keep the plants small.

I'm in the early stages planning a stealthy grow cabinet, and if/when these start to get a bit bigger, I'll put two of the plants in there. The smallest one will stay on the window sill.

* - Only for the largest seedling. The middle one sprouted a day later, and the smallest one did not appear until day four.

Crow River said:

Thanks for the info. Really detailed!

For additional lighting later in the grow I have an 18W "daylight" (6500K) ceiling/wall mount circular LED array which again I pulled from a domestic setup to install "warm light" replacement. It's rated approximately 1500 lumens but is 35cm in diameter and gives a much more even spread of light than the ordinary bulb. Subjectively appears to be quite a lot brighter too. I've removed the translucent shade so the plants will just get light from the bare LEDs.

So if I use these lights during vegetative stage I should keep them quite close if I read your information correctly? I've also heard that a "warm white" bulb might be more effective during the flowering phase?

Click to expand...

PPFD maps are indeed super handy as light intensity can be more or less impossible to estimate with our eyes.
Keep in mind that while removing the translucent cover increase light output and make it more direct, it will also expose conductive parts on the lamp. Oftentimes, cheap lamps don't have an isolated driver inside it, which is supposed to physically separate the high-voltage side from the low voltage side. In short, touching any conductive parts on the front of the lamp while it's operating can, if unlucky, be about as bad as putting a knife directly into the electrical outlet on the wall. Here's a good read about isolated VS non-isolated drivers by Mean Well, if you want to learn more.

If you do decide to upgrade your lighting and want to keep using mid-size E27 solutions as grow lights, we've made an E27 lamp just for this. It is using the efficient Samsung diodes that we all love. Pulling 36 watts, it puts out 5335 lumens at 150 lm/w. It is also fitted with an isolated driver, and the lamp is CE-certified to be used safely without any cover on the front, with no risk of getting an electric shock.

You can find a couple of different PPFD maps on this page, but I'm also attaching some of them below for you to easily compare the light footprints to the household bulbs.

Thanks for the tips and information. Indeed the driver is right there in the lamp. I make sure not to touch it when plugged in though. I will be building a grow cabinet and initially will add a couple of these fittings on the side walls to supplement a ceiling hung grow lamp. Reckon I'll put the diffusers on them though, partly due to angle of incidence but also to avoid brushing accidentally any exposed contacts. If I start another grow after this one I'll maybe look into upgrading the lighting. The wiring will be there so simple enough to swap out fittings.

Day 14.

Waiting for these togrow a few more leaves and then I'll transfer to final pots.

I noticed that roots were starting to poke through the paper pots from two of the seedlings, so I repotted them last night. Two went into 5.5 litre pots, they will go into the cabinet once it's ready. The smaller, later germinating seedling did not have roots showing, but I repotted it anyway, into a 3 litre pot. It will stay at the window until flowering, so I want to keep it small and manageable.

Temperatures at the window sill about low today, sky is overcast and windy outside. Propagator packed away, I have a heated mat under the pots and popped some clear plastic over them as a makeshift cloche to help warm things up a bit.