Growing fruit / veg indoors - artificial lighting - Help

I don't want to be a wet blanket, but, the cost of light and possibly heat could make your veg gold plated. I don't start to put heat in my tunnel until the beginning of march and that costs enough.

Not at all, that's why I'm here. I have zero experience in this and this forum is packed with people with great knowledge.

I've read about LED's (expensive to buy outright but cheaper in the long run) A 150w Halide won't cost the earth to run 10-12 hours a day (around £5 per month) But I don't know enough to judge how many Halides will cover what area, if halides are even any good etc.

Just looking for peoples feedback and advice that's been there/done that sort of thing

Led grow lights are cheap to run and give no heat and last years and can grow all the things you mentian probkem is there not to cheap to buy

I find a shop light great to start my stuff in February and March/April. But after that mother nature provides. Trick is to grow as much as you can during the growing season and store/preserve it. But I guess if you have deep pockets and a genuine interest in doing it go for it. When I was researching I found the best advice was on smoker's sites. Not what I was looking to grow of course but the info is broadly the same and these guys are pretty fanatical and generous with technical information and advice.

i know nothing about this but my partner who is known on such sights suggests compact flourescent lights or flourescent tubes. both of which are common household bulbs and are avaliable for our purposes in 3 types 2700k which is for flowering and fruiting, 6500k(harder to find) for growing vegatation and finally duel spectrum such as grolux.

on the subject of the tubes they come in t5,t8,t12 ect... the bigger the number the less energy efficient it is, however t5's are significantly more expensive then t8 so everyone uses t8.

on the subject of CFL's more small ones are better then few powerful ones as you can distribute them more easily around the foliage and can go much closer without causing heat burn.

for more clandestine plants the recommendation is up to 1kw per plant but you can get away with lot less especially in pre flowering veg growth.its up to the grower to watch for stretch between nodes and add more light accordingly

Thanks for the replies.

Redser I will have a look on for some sites, thanks.

Kazborn,

As for T5 bulbs, I'm currently 6 x 39w T5's on a reef tank right now for coral growth but am in the process of switching from these to Kessil A150 LED units, so I would have these spare to use.

I have six 39 watt (3 foot) bulbs and reflectors with mixed spectrum's, lowest from 6500k (lots of blue and red) up to 14k white that I could use then?


I was hoping it would be a case of, there's a link to a light, there is a list of what it grows....on you go lol. II think trying to work this out is going to be a bit more difficult than first thought...

it should be ok he says anything outside of 6500k or 2700k might be wasted heat and energy but might be fine he hasent heard of anyone else growing with spectrum other than these

Gro-Lux T8 26mm tubes - Fluorescent — (UK) Light bulbs, halogen lamps, spot lights and tubes by mail order in the UK

these bulbs are pretty much light and go as they cover all the light needed to feed a plant.
the light they emit looks purple and not as bright as a normal bulb of the same wattage, which is a sign its not wasting energy on too much visible light.

Purple light pouring out my spare room window, the neighbours are going to be convinced I'm growing something more than fruit in my spare time lol.

Thanks for the link, Kazborn. Pity it's T8 bulbs, will need to buy a starter unit for it. Got T5 starters coming out my ears!

Sorry for all the questions but most things you can grow in the house, within reason, can be grown under the Gro-lux bulbs? Chilli plants, berry plants etc?

yes and they do t5's aswell =)

I was just wondering how powerful sunlight was. I found this


How Much Solar Energy Hits Earth? | Environmental News, Articles & Information | Global Warming News | EcoWorld

But I assume that is at the equator at midday on a cloudless day. 1/2 the time there is no sun, and it is usually coming in at an angle and of course plants only use a small part of the suns energy spectrum, the blue and red.

So I guess if you were in a 12'x12' room with a 100 watt light bulb for every square foot, ie 144 of them, I guess that would feel like the equator at midday in full sun.

It sounds about right

I could be growing banana trees with that much power... or invite the family up to the room for a week and save them going on holiday abroad lol

I'm thinking that if these plants I'm planning to get grow well on a sunny window sill, then a light above them in a warm room should suffice just as wel, which would let me get on with things from now till next spring when I get can them outside back into the garden.

I'm considering a rack setup to begin with. I've got to units that are 4ft x 2ft footprint, with a shelf 4 inches off ground level, then 4ft above the bottom shelf there is the second shelf - which againis 4ft x 2ft. I'll be using two of these units next to each other to begin with. It works out 32 square feet, which sounds a lot but really it's hee haw lol. Planning on berry plants on the bottom rows, chillies along the top rows.

Lighting this I was planning two 4ft Gro lux t8 bulbs with reflectors over each 4ft section. So 8 bulbs in total. Unsure to how long a light cycle yet. 12 hour possibly?

Going to do do tomatoes in the garage, the plants are too big for my liking indoors, and with green fly is it? That could be a bit of a problem as well. There is a decent sized window with a bench underneath it in the garage so I'll make a mini green house round it with either a roll of clear plastic surrounding it on a frame or some plastic sheets on a frame with access.

im afraid cfl dont work that way because of something called inverse square law.
sunlight has travelled millions of kilometers to get here so a few leaves in the way means nothing to it but cfl only have an effective range of a few inches. so if a leaf is in way of a flower site it will not eat. high pressure sodium bulbs are about the best we can synthesise so lots of small cfl's are the best you can get at the minute for light penetration to many sites on the plant.

im not sure about this sunlight being the equivilant of a 100 watts as you compare a plant fed 100watt per square foot to one grown in sunlight and you will see there isnt a comparison worth mentioning....... sunlight is king cfl just fill in when it is absent.

P.A.R is the true measurement of the useful light from a source, watts and lumins actually mean nothing to a plant which could starve under 10000watts of light if its the wrong kind.

it depends on what your growing. for the plants this knowledge is gained from, if they recieve 12 hours or less they enter flowering mode. whilst on greater than 12 hours of light they continue to just grow vegitation. For plants that behave in the same way as this, there is something called 'gas lantern routine' which is an old technique ressurected for modern uses. in GLR you run 12 hours of light then 5.5 of dark, then lights go on for 1 hour to break the sleep cycle and prevent flowering, then off for another 5.5 hours. using this system confuses the plants into thinkiing its almost time to flower and the grow with increased vigour to try and be ready.

I take your point kazborn, it is rather complicated I was just trying to get a rough idea.
I mean the room I am in is 12x12 foot and if it had a light bulb for every square foot it would be pretty hot in the room, I think it might feel similar to being in the middle of the sahara!

Now were my 100 watt bulb surrounded by a circular lampshade with surface are of one square foot, that surface would be in similar conditions to the surface of the sahara on a hot day.
Now if there are reflectors above the light bulbs you are getting about 100watts per square foot.

The UK is at a latitude of 53.1142°, if my maths is correct we get the cosine of that which is 0.6, rather more than I thought, or our room is full of 60 watt light bulbs!! But we also have more losses in the atmosphere as it has more to travel through at that angle.

But we are on a tilt an only at that angle on the equinoxes, which are March and September I think, we get more in summer and less in winter.

Now you could use maths to work out a suitable distance for your light bulbs I believe.

What you need to do is work out the radius of a sphere with surface are of 1 foot, assuming you are using a 100 watt light-bulb.

so...let's do that!!

The surface are of a sphere is 4 pi x radius x radius ( 4pi.r^2) so 4pi.r^2 = 1

r^2= 1/4pi so r = square root of (1/4pi)

4pi = 12.5, 1/4pi = 0.08, sq_root(1/4pi) = 0.282

So you want 0.282 feet or 3.385 inches.

That would be at the equator though


Here you need about 0.68 of a foot or 8 and 1/4 inches if my maths is correct.

[square root of (0.6/4pi) feet]

That assumes you are using a bulb emitting the same spectrum as the sun, grow lights are different usually. They are somewhat artificial as they miss out the green light.
I don't know if that affects plant growth much, id guess if speeds them up if they get extra blue and red to compensate.

Of course you don't get sun all day either but I doubt all day full sun does any harm, more good I expect.

It might be cheaper to move to oz for the winter..........very interesting thread though........there seems to be a lot of germinator input!!

Perhaps because some of the more experience growers here have realised the cost benefit ratios just don't work for VEGETABLES!!!!!!!! Man......