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cjohansen_gw

Lighting in DIY grow box

cjohansen
11 years ago

I'm on my very first chili growing adventure (really, the first time I'm growing anything). I started out sowing two seeds each in 10 coconut pellets and kept them in a small lidded plastic box in my bathroom, where there's underfloor heating. So far, so good, 9 days in, 19 out of 20 seeds sprouted.

This weekend I built a grow box out of a cardboard moving box. Clad the inside with aluminum foil (including a lid), put the seedlings in small plastic cups and attached two fluorescent light tubes(?) about an inch away. Lid goes on top and air comes in via the moving box handles (holes on the sides). Temperature inside is roughly 23C.

After watching people on YouTube, I worry that there's not enough light. Im using two 8W tubes. I went low so I wouldn't have to worry too much about heat/confined space and associated fire hazard. It looks pretty bright to me, but is it way too little light? Seedlings are growing and look healthy, but it's only been 3 days at the most.

Also, roughly how often should I water them? I understand that they should pretty much dry out between waterings, but should it be roughly daily, weekly or something in between?

Any help is greatly appreciated!

Comments (36)

  • ab2008
    11 years ago

    According to what a few folks have told me, just let the dirt get dry on top between watering. I think its just something to watch and not any specific time.

    I check mine twice daily. Of a morning, and evening. Sometimes they need watered, sometimes they don't heh.

  • tn_gardening
    11 years ago

    Since it's cardboard, you can cut some holes in your box for ventilation and/or remove the lid (heat is most beneficial when germinating)

  • teyo
    11 years ago

    About the lights, you'll have to tell us how many lumens those tubes give out for a better estimate. I'm fairly certain they're quite weak though, how long do you plan on having the plants in the growbox? If they get big they'll need significantly stronger lights, if you're intending to grow them fully indoors then a hps light will be the way to go later. If you just want them to get a good start before putting them outside, then tubes will do fine, just check that they have a decent number of lumens. You can also look into cfl's, less of a fire hazard and a fairly cheap 30w one will give out 2000 lumens.

  • cjohansen
    Original Author
    11 years ago

    Thanks everyone!

    @teyo: I'm planning on eventually moving them outside, but I do live in a fairly cold climate (Oslo/Norway), so if the summer doesn't quite pan out, I'm thinking maybe they'll stay close to the window. For now the plan with the grow box is just to give them a good start. It's probably too chilly by the windowsill at this time a year, and there's not a lot of hours of sun - some days are grey from morning to evening.

    I'm not sure how many lumens these put out, I'll have to go back to where I got them to check. Could you be a little more specific about "a decent number of lumens"? Is said 2000 lumens "a decent number"?

    What are cfls?

  • ab2008
    11 years ago

    I am also quite curious about this though however.

    I have some lights... http://www.walmart.com/ip/Lights-of-America-24-Fluorescent-Grow-Light-Fixture/16879945

    Color: 4200K
    Lumens: 1093

    I am kind of unsure what plants need the best of as well. They seem to be okay so far, but I'm unsure of how well they will do in the long run as they just only started sprouting.

    (Not meaning to hijack the post, but I think it kind of falls under the same thing the OP is wondering.)

  • cjohansen
    Original Author
    11 years ago

    I just tried to Google the tubes I've got. As far as I can tell, I have T5 tubes. According to an article on light tubes I just read, T5s should be able to output up to 100 lumen per watt in ideal conditions (35 deg Celsius). I also found 8W T5 tubes around the net with stated output of 3-700 lumen. So if 2000 is "a decent number", then I'm a bit short. Will get two more of the same kind for the box next weekend.

    I also have another plastic box with 24 compartments that I sowed yesterday, will have to put together another bigger box that can fit bigger lights.

  • DMForcier
    11 years ago

    The tubes should have the lumen output stenciled on them (this may be a US-only requirement). Weak light isn't fatal, just less than optimal.

    I worry about the air circulation. The handle holes aren't really good enough - you want air circulation. Can you run a fan in the room or at least leave the box top off for a few hours a day?

  • cjohansen
    Original Author
    11 years ago

    I have a fan that I can hook up next to the box. I put the lid on mostly to maximize reflected light and to keep the temperature up. Taking off the lid drops the temperature maybe 1 deg Celsius, but as I understand from this thread, that isn't fatal. I guess whatever light is reflected back from the lid will be so weak it won't help the plants much anyway.

    I raised the lid into a ^ for now, which lets in more air, and will hook up the fan tomorrow. I guess there shouldn't be too much of a draft? Maybe just run the fan a few hours in the evenings?

  • DMForcier
    11 years ago

    Good idea on the A-frame roof. Air movement will toughen up the stems, and you want to evaporate some of the moisture in the growing cells. You could leave the fan on all day provided that the temps stay up. Watch that the cells don't get too dry. (It's a balance kinda thing.)

    Sounds to me like you've got a good start. Pics would be good.

  • cjohansen
    Original Author
    11 years ago

    Thanks so much for all the help. I'm working from home tomorrow, so I'll turn on the fan in the morning and keep a close eye with the plants all day. Since sowing these guys little over a week ago, I've gotten completely hooked :)

    Attached photo shows my little "casa de chile".

  • cjohansen
    Original Author
    11 years ago

    ...and here's what it looks like inside.

    (On the previous picture it's dark because the lights go off at ten in the evening. I switched 'em back on for the picture inside the box)

  • cjohansen
    Original Author
    11 years ago

    One more question: When do I start using fertilizer?

  • teyo
    11 years ago

    You need as many lumens as you can muster up, i'd say 1400 for the whole box is too low. I have 4 tubes at 1600 lm each, and i think i'm barely getting enough for them not to stretch.
    Cfl stands for compact fluorescent (bulb), google them, you should be able to find them in any hardware store or home equipment store. Cfl's go into a regular lightbulb socket, so you can basically string 3-4 together in a bunch, they are a bit easier to handle that tubes. But if tubes are easier then go with that. You should also compare prices in your area, it is possible that 3-4 cfl's or tubes would cost more than a lower wattage hps, which gives out waaay more lumens than either of these. A hps lamp needs a starter and a ballast, hydroponics stores sell them in packages so it's easier. One flaw of hps bulbs is that they give out more heat, and have to be set about half a meter or more from the plants, depending on wattage.
    Also, the spectrum of the fluorescents needs to be around 6500 k, that is ideal for vegetative plant growth. A hps gives out a full spectrum and can be used for both growth and flowering.

    If i were you, i'd go with a hps settup. It may cost more in the start, but since you have a short season by the time the plants go out they might already be flowering under hps. And when your season is over you could just put them back under the lamp (not all of them but a couple sure, depends on the strength of the light) and have them continue flowering and fruiting all winter long. The drawbacks are probably the initial price, more heat output and maybe the electricity bill if you go crazy and get a 1000 w light :)))

    Dig a little on indoor growing sites, and your local stores to see what is the best cost and resources wise :)

    Edit: for some reason i misread that you would have 20 plants :))
    If it's only these 4 getting 2 more tubes might be enough to keep them growing until setting out. if i were you i'd still research into hps, with something like a 150 or maybe even 250 W i think you could have them fruiting all winter long. Depends if you want to keep them after the season is over or not.

    This post was edited by teyo on Wed, Feb 13, 13 at 3:30

  • cjohansen
    Original Author
    11 years ago

    Thanks for the input @teyo. I looked around and now know what CFLs are, and more importantly, what they're called in my language :) Will go shopping this weekend.

    I have now started worrying about leggy plants. When is a plant too leggy? Is it the distance between set of leaves, or the size of the leaves relative to length of the stem or what? My biggest seedling has only one set of leaves (cotyledon?). It's about 2 inches tall, leaves are almost 1 inch each, and the plant was 1.5 inches away from light. Moved it up to 1 inch now.

  • teyo
    11 years ago

    i don't think yours are leggy, at least from this perspective.
    seedlings are most vulnerable to stretching from the time they sprout to when they develop first true leaves. if light is inadequate the stem will stretch trying to reach the light and eventually the plant will topple over and die. also they get very prone to fungal attacks.
    see here an image i got off google of leggy pepper seedlings:
    .... sheesh this forum software sucks bigtime, won't even let me post a link... yeah sc*** you too gardenweb.
    please google "leggy pepper seedlings" to see some examples

  • cjohansen
    Original Author
    11 years ago

    Went by the hardware store today. The best I could find was a CFL "2d" bulb/tube, like this one: http://www.jula.no/lysror-2d-3500-lm-425056 The best I could find was 4100K and 1600lm. At the very least, that's a vast improvement over what I have today. 4100K was the highest color temperature I've seen in any store so far.

    Unfortunately I couldn't figure out what kind of lamp/attachment it goes into, and neither could two of the people working there. The bulb has four pins (2x2) in the middle. I postponed buying to see if I can figure out what kind of attachment goes with it.

    An interesting thing happened since I left the office some hours ago: Most of the seedlings have changed their cotyledons from being more or less horizontal to pointing more upright. Cause for alarm? Are they striving for more light?

  • habjolokia z 6b/7
    11 years ago

    Check this out for CFL

    http://www.jula.no/kompaktlysror-g24-3050-lm-421337

    Not sure but I think it's 3000k or 3050k?? Not sure if they have anything higher than that

    Mark

    This post was edited by habjolokia on Wed, Feb 13, 13 at 18:36

  • cjohansen
    Original Author
    11 years ago

    Scratch that! Finally found a bulb that goes into a regular socket that has 6400K and 30W effect: http://www.elektroimportoren.no/sparepaere-30w-150w-15cm-e27-6400k-cool-daylight/3802328/Product.html

    It doesn't state the amount of lumens, but it seems CFLs output somewhere between 50-70 lumens per watt, so I could expect 1500+, which looks good. Gonna get four of these. Now just need to find the cheapest possible socket to put them into.

  • teyo
    11 years ago

    Yeah i think that won't work. The color temp is way too low for growth, those bulbs would be ok for flowering and fruiting (though not the 4000 one), but for growth you need more blue light, coolwhite, daylight, stuff like that...
    The thing is fluorescents give out a relatively narrow range of wavelengths, and plant chlorophyls have apsorption peaks at quite specific ranges, although some light is apsorbed outside those ranges by different pigments. But not enough for growth/photosynthesis...
    If you can find a couple more of the tubes you have now it would be better than putting a wrong temp light. Then you'll see if you need more light, and you'll buy some time to research, as i said grow shops, then ebay, i took a look at hydroponics.eu and saw some pretty strong cfl's for 28 euro for instance, you'd probably get them for less on ebay.

    Edit: I think we posted at the same time, my post was refering to you earlier post, a 30w 6400k would be great, 4 of those would kick butt ;)

    This post was edited by teyo on Thu, Feb 14, 13 at 3:04

  • cjohansen
    Original Author
    11 years ago

    Now we're talking! Took a trip to that store, and this, apparently, is the place to go for proper lighting in Norway. Lots of proper daylight bulbs and tubes, and cheap. I got four 30W/6400K bulbs, some sockets and wires. Will post picture once I've assembled it all.

    While I was there I had to resist the urge to buy a 2m wide reflective fixture that could hold 2x58W tubes of 6400K for a total output of 10K lumens... Unfortunately the size would've required some, uhm, "upgrades" in my home that possibly would have, uhm, "surprised" my girlfriend ;)

  • Bill_Missy
    11 years ago

    Not trying to highjack a thread by any means. I am currious as well as this is some great info. If I am reading this correctly, the setup I have is crap?

    Sylvania Daylight Full Spectrum 48"/40 Watt
    2200 Lumens, 40 Watts, 20,000 Hours, 90 CRI, 5000K, Two T-12 Bulbs.

    Bill

  • habjolokia z 6b/7
    11 years ago

    Bill_Missy here is what I run T12 also

    Two 40W bulbs T-12. One is a Ecolux plant grow light 1900 Lumens. The other is a Westpointe, F40/universal/WP, cool white, 3,150 Initial & 2,860 Mean Lumens.

    Using this the plants do very well

    Here is a pic from last season using those lights

  • teyo
    11 years ago

    um, Bill_Missy, NO it isn't crap :)) it's a bit towards the warm spectrum, but it should make up for it in light intensity i hope. the t12 bulbs use a bit more power for the same lumen output (compared to for instance t5's which are high output lights, more efficient at the same wattage), but they should do just fine as long as you keep them close to the plants.
    mine are t8's and they are working so far. i might have problems later on when the plants get bigger but i intend to put them out by then. and scrap up cash for a decent hps light by next winter.
    peppers are nice in the way that when they don't have enough light (not as seedlings, when they're a bit bigger) they will just slow down in growth, same as when the temp is a bit under their liking.
    your plants will tell you if they like the lights or not, always best to listed to them first :)

    i will try to dig up some texts about indoor garden lighting, it will make it easier for you guys to read the how's and the why's, and then see if you need more light for your plants. there's a ton of factors involved.

  • cjohansen
    Original Author
    11 years ago

    A couple of more questions :)

    1) My seedlings have grown a bit leggy. I'm not too worried. But I have noticed they start each day with their cotyledons outright and in the end of the day they all point upwards. Are they reaching for more light? They're getting new lights today.

    2) The new bulbs I got will be quite a bit warmer than my current tubes. Also, I learned that the plants need circulation. I'm thinking of building a new box where I hang the bulbs from an aluminium foil clad lid and remove one of the sides of the box so I can vent it properly with a fan. Does this sound like a decent idea?

  • habjolokia z 6b/7
    11 years ago

    Yeah agree the lights are good and better than what I use here is another pic as the plants last season that were at a later stage and they did fine until I got them outside.

    The two bigger one were my fast growers a Bell pepper for my Wife of course and a Cayenne. The smaller ones were Ghost, 7pot, peppadew, alma paprika, habanero and a few more

    Mark

  • jifjifjif
    11 years ago

    I am going out today to buy a light fixture myself and rig it all up this weekend. I have 5 of 12 cups sprouting, so now is the time.

  • teyo
    11 years ago

    @cjohansen
    1. i think that is normal. sometimes they can react that way to too much water, so check that you're not overwatering them. though as i said, it could be just the way they grow, some of mine do that too and they're all in the same conditions
    2. you can get the air to circulate using a small computer fan, or two even but i doubt you'd need two. peppers don't mind heat that much, but still i'd be a bit more careful when they're young.

    @habjolokia those look really nice and healthy!

    i'm having trouble locating some great articles i read quite some time ago, in the mean time i'd like to comment on something i find very interesting.
    Up until quite recently, indoor lighting and growing was thought to be associated strictly with marijuana growers, especially on such a small scale as a couple of plants indoors. it is very interesting how things are changing and how people are recognizing that there is nothing special or daunting about indoor growing, other than making life easier for people in colder climates. This was helped immensely by new lights like high output fluorescents, which make indoor grow lighting affordable and not intensive on the electricity bill.
    The next big step, and we are really close to that, is the reduction of price for led grow lights. LEDs give out a very narrow spectrum of light, and led grow lights are tuned to the absorption peaks of chlorophyl, so there is less power used and most of the light is absorbed.
    now, don't go rushing to ebay and buying cheap panels from china, they aren't good yet. good leds are still expensive, but their price is dropping rapidly,and in a couple of years the ordinary gardener will be able to afford them.
    another thing, since grow lights were really used mostly by weed growers at first, so their circles are way ahead in growing techniques and especially DIY equipment. if you want to read some really great tutorials on building your own grow boxes,reflectors and stuff, i'd suggest taking a look at places like grasscity forums,thc talk or something like that. since this could be a sensitive topic, please understand i do not condone or advocate mj in any way, only the nice collection of diy ideas and tutorials on equipment that can be found on such sites, and which are very rarely seen in books, let alone all in one place.

  • cjohansen
    Original Author
    11 years ago

    @teyo: You don't need to look for information on growing peppers for more than a few minutes before you realize that weed growers are _very_ actively discussing most of the same topics :) After starting to grow these guys I have also had almost every person I know make the "weed grower" joke...

    Re: circulation. All I have is a rather big fan that I use for myself on hot summer days. I've been running it from a little distance that seems to do fine. I was planning to make the next box with a lid, but one open wall mostly because it's easier to have the fan blow air in from the sides than down from the top. We'll see how it works out.

  • teyo
    11 years ago

    yeah you have to also give them credit on creativity, they have some crazy good solutions and ideas :D i've heard plenty of weed jokes too, and i don't even bother with a grow box :D

    oh one other thing i forgot, if you're lining the box with ordinary kitchen foil, try to use the matte side of it, the shiny side can concentrate light in much the same way a magnifying glass can, and if your lights are strong enough and such a point hits a plant in just the right spot it can burn it. that's why people use mylar foil or even plain white styrofoam panels. though with cfl's i'd say the danger is not that great.

  • cjohansen
    Original Author
    11 years ago

    Got it all hooked up. So far only three bulbs, as I wrecked one of the sockets :( As expected I am a little worried about the heat (i.e. fire hazard) in these things, so I suspect I will use the old box for when I'm not home. It's pretty bright in there now at least :)

  • jifjifjif
    11 years ago

    That looks good, cj.

    Here's my little rig:

  • cjohansen
    Original Author
    11 years ago

    Thought I'd post a quick update. On my third habitat now. The box got too warm, and eventually too small so I've constructed two frames that are pretty much open. Inside there will eventually be 54 individual pots and 6 30W 6400K CFLs. Having a lot of fun with this project :)

  • DMForcier
    11 years ago

    The plants must find this highly confusing.

    "There are three (soon to be six) suns in the sky! Which one do I track ?!"

  • cjohansen
    Original Author
    11 years ago

    I'm now at full capacity. Plants don't seem confused at all, DMForcier, quite the contrary :)

    Unfortunately I'm slowly realizing that I don't have room for anywhere near this many plants once they start going into huge containers. Not looking forward to killing 'em off or giving them away :(

  • DMForcier
    11 years ago

    Whatever you do, DON'T NAME THEM.

    (Very nice looking plants, btw.)

  • ab2008
    11 years ago

    DMForcier,

    But... George was one of my favorites! :(

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