Return to the Growing under Lights Forum | Post a Follow-Up

 o
CFL lamps near window - input please

Posted by bedtime 6a Southern Ontario (My Page) on
Sun, Aug 18, 13 at 14:35

No problems here. Just would like some input on my setup:

The weather has started to cool off and I have brought some of my herbs indoors. The picture below is my 'harvested to the root' chocolate mint (left) and spearmint (right). Lamps are CFL bulbs, 44W (150W equiv) apiece. One is around 6500k and the other 5000k, the latter will be replaced when I get to it.

The lamps seem to put out about 100000 lux at 1" and about 20000-50000 luxat half a foot as measured by my android. The sun through the window is around 180000 lux on a bright sunny day. I decided on putting the plants in the window so I could take advantage of this fact. Much of the day there is no direct sunlight, so the lights are necessary.

As you may have noticed the lamps are clamped on and bent at a certain angle and near the edge of the container. This is to allow the lamp light to hit all the plant whilst letting the sunlight also shine on it. The issue I can see here is that the plants foliage will be facing the lamp, and when the sun comes out and overpowers, the plants wont be facing the sun. If I were to have the lamps directly on the plants a way that would make the plants face the sun, then the lamp itself would block the sun from getting to the plants.

I'm thinking of putting a clear plastic bag over the containers to keep the moisture in but I'm thinking that wont really be necessary for mint plants.

The harvest was great and I'm hoping to be able to harvest in 2 months as this plant is said to produce a harvest every 6 weeks. I'm looking for any suggestions or advice you might have.


Follow-Up Postings:

 o
RE: CFL lamps near window - input please

If you put the lamps directly over the plants in a way that it doesn't block the sun why wouldn't it work?


 o
RE: CFL lamps near window - input please

slimak,

Yes, but then I would have to increase the distance to the plant and so I'd be reducing the lux considerably. I think I could likely do that once the plant grows a little bigger and starts coming out of the pot.

* update *

Made a small burn on both plants by having the bulb much too close (about 1/2"), moved to 2" away. Already seeing several buds come up on both plants. I think I'll mark the progress with photos and let these plants race eachother. My bet is on the chocolate mint, but time will tell.


 o
RE: CFL lamps near window - input please

You're growing herbs. Your lamps should be enough to get them going :) I keep my young seedlings about 10" from my fluorescents and they are growing like crazy. My air temp is too high (77 degrees) so if I put the lights any closer my plants don't like it :) The lower the air temp the lower I can get the lamps to work without burning the plants.

Besides these are cold crops and as you can see here
http://bonnieplants.com/products/chocolate-mint
they like full sun to part shade so giving them too much light and high air temperature is not good.

Move it away and see what happens


 o
RE: CFL lamps near window - input please

slimak,

I find seedlings seem to grow decently under tube fluorescents for a while, and then once they reach a certain size they need more powerful lighting to get the light to all parts of the foliage. If I were to more the light 10" away I'd lose a tremendous amount of light to the plant.

Tomorrow I'm going to check the temperature of the plants and go from there.

Btw, does anyone have any idea what on/off cycle of lighting is best? Currently I'm doing 12 on, 12 off.


 o
RE: CFL lamps near window - input please

I beg to disagree my friend :) this was taken a week ago, they're larger now and peas fruiting. Put some white plastic film that doesn't burn half way around the buckets so the sun gets to it if you want to do it this way and you'll be set.
I keep mine on 14 hours on cycle. The only mistake I did was that I waited to long to transplant them into bigger pots sooner :) They probably be huge by now if I did that


 o
RE: CFL lamps near window - input please

peas, 4 weeks after seeding


 o
RE: CFL lamps near window - input please

peas flowering and fruiting


 o
RE: CFL lamps near window - input please

I get about 40w per square foot with my lamps. That's same or less than you are getting.


 o
RE: CFL lamps near window - input please

slimak,

I like the idea of the plastic film around the back half of the container and I might try that.

It seems your situation is a trifle at variance with mine. You are growing from seed, and at this point in time those plants don't require as much sun. After they grow to a few feet you'll likely start to see a slow down in growth.

My situation is I have a rather large root system with an almost insignificant amount of foliage to feed it. I would think it would need as much light as it could get and as soon as possible to push some energy into it and keep up its vitality.

As for the burn, I found out what caused it. I noticed there was a little bit of crust on my CFL light, which happened to be right where the burnt stem would have been. What happened was I must have bumped another plant into the lamp and it moved it. Problem solved there.

One issue I might have is the top of the soil drying out, before the bottom does. This is going to make watering tricky. Currently the top is dry but from the weight of the containers I can tell the plant has more then enough water.

I'll post pics soon of the plants progress.


 o
RE: CFL lamps near window - input please

I really don't understand your approach. You're saying that you barely have any foliage and you want to bombard those little leaves with light even though they don't need that much light since they are small :) they can't take the heat as big leaves would be able to do. So when your plant is trying to develop top growth instead of putting energy into growing towards the light it fights with the light because it's too close making the leaves burn :)
The foliage is an energy factory using light to produce it. A factory can produce as much as its size let's it so if you have 20 trucks full of light waiting outside it's not gonna make the factory produce more until the factory size expands. In fact it will destroy the little factory because you got 20 pissed off truck drivers creating heat :) always just try to have just one truck outside so there is steady production but not too much heat.


 o
RE: CFL lamps near window - input please

Secondly, your roots . I hope that you have good drainage and just keep the soil moist enough so they don't dry out. If you don't have holes on the bottom of those buckets you'll drown your roots. Since your top growth is small still it won't use much water since the factory doesn't need it yet. It doesn't matter if it's water, light, temperature or nutrients, too much of anything is not good. In fact a little deficiency does the plant growth good , roots grow out faster in search of water at the same time get their oxygen. Top growth speeds up in search of more light instead of trying to keep itself cool growing bigger leaves and branches to support them.


 o
RE: CFL lamps near window - input please

In conclusion your plant will show you what it needs you just need to be able to read the signs and act accordingly. Look at the development of the stem, how the leaves curl, color of the leaves etc.


 o
RE: CFL lamps near window - input please

slimak,

I have very good drainage; 5 holes in the sides and a 1 1/2" hole in the middle, plus 4 slits going down the sides of both containers, which allows me to pry it open and take a look a the roots progress. Air enters through here as well.

Pictures are posted below and I don't see any indication of burn marks from the lamp. You made a great point about 'a little deficiency' and root and bud growth. I find the top of the soil is dry but the 4/5 underneath is moist, so I'll just leave it for now.

Spearmint:


 o
RE: CFL lamps near window - input please

One further thing. The 5000k light was used with the Chocolate Mint plant, the 6500k with the Spearmint, I've switched the bulbs today. Perhaps this is why the Spearmint plant is growing faster? In any event, time will tell.

Chocolate Mint:


 o
RE: CFL lamps near window - input please

well, it looks good :) In my opinion 6500k is the way to go, more plant usable blue light spectrum. They are different species and some plants just grow faster than others so it's hard to say what the reason is.


 o
RE: CFL lamps near window - input please

* update *

It has been about 9 or 10 days since both plants have been cut down to the root, and at present it seems that the spearmint plant is growing much quicker. Of course, there are so many variables that could affect this...

I bought a new electrical timer outlet from the dollar store for $3 and an extension cord that splits into 3 way or another $3. I've set it at 16:8 on:off, 5am - 9pm.

slimak,

I added a small panel that will help to reflect the light back into the container, as you suggested. Seems to be working great. I'll post it in the next photo. Just want you to know that I appreciate your advice and conversation.

Chocolate Mint:


 o
RE: CFL lamps near window - input please

Spearmint:


 o
RE: CFL lamps near window - input please

I'm glad I could help. Good call on implementing the electrical timer, makes life a lot easier : )
Yeah , the reflective walls make it a lot more efficient. When you get some time post a pic of your improvement. Plants look great!


 o
RE: CFL lamps near window - input please

This only two days later and there is considerable growth. It seems that the biggest leaves (and even the stems are much thicker) are near the reflector, which happens to be where most of the light is pointing. Almost all of the leaves are pointing to the CFL light, and not to the sun, so perhaps this plant could be grown just fine with artificial light alone? Though this will likely change as the plant gets bigger.

The spearmint plant is far outgrowing the chocolate mint.

Spearmint:


 o
RE: CFL lamps near window - input please

Strangely, this plant has the least growth where the light is directed and more where the sun is shining. Likely because of the 5000k bulb on this plant.

Chocolate Mint:


 o
RE: CFL lamps near window - input please

Sure, you can grow them completely under artificial light, why not :) People grow big tomato plants under lights so your mint plants wouldn't be a problem.

As far as your growth difference goes, I'm sure the reflector does help but also leaves that are farther from the window got a head start and get longer duration of sun due to the fact that your ground level is about 2 inches below the top of the bucket :) So as you can even see on your Chocolate Mint picture the first leaves closest to the window are in shade so when the sun goes up or down this area of the bucket will always get less light throughout the day.


 o
RE: CFL lamps near window - input please

Maybe it is just me but IMHO you have way too many plants growing in those pots. Although I have never grown mint in pots I have in the ground and if I remember correctly the spacing should be about 8"-12" in between. So 2 plants, maybe three, would be your pot max. Looks like you have 30-40 growing in each. I would cull to the largest and watch them flourish.

SCG


 o
RE: CFL lamps near window - input please

SGC,
This is just one plant. That is the way it started and splitting the plant would only result in more plants. At least for now they all share the same root system, as opposed to competing for resources.
The picture below was taken 16 days from the time of the plant being harvested to the soil line.


 o
RE: CFL lamps near window - input please

Bedtime , I think you should be fine. My mother grows mint in a pot too and she has about 20 stems sticking out of it. Plus look at this http://images.search.yahoo.com/images/view;_ylt=A0PDoTECFCZSnX8AnNyJzbkF;_ylu=X3oDMTFyYjB2MXRsBHNlYwNzcgRzbGsDaW1nBG9pZANlNjU5MmE3OTcxY2VjNDBkMTJlNDUxYTAyYzhiNTAwYgRncG9zAzU0?back=http%3A//images.search.yahoo.com/search/images%3Fp%3Dmint%2Bplant%26fr%3Dyfp-t-143%26fr2%3Dpiv-web%26tab%3Dorganic%26ri%3D54&w=1600&h=1200&imgurl=curiouscuisinier.files.wordpress.com/2013/03/mint-plant.jpg&rurl=http%3A//curiouscuisinier.wordpress.com/2013/03/17/vanilla-bean-brioche-with-vanilla-honey-butter/&size=698.2KB&name=%3Cb%3Emint+plant%3C/b%3E&p=mint+plant&oid=e6592a7971cec40d12e451a02c8b500b&fr2=piv-web&fr=yfp-t-143&tt=%3Cb%3Emint+plant%3C/b%3E&b=31&ni=160&no=54&ts=&tab=organic&sigr=130rluhop&sigb=134umh850&sigi=11rumgtop&.crumb=hS7MQ8WJI48&fr=yfp-t-143


 o
RE: CFL lamps near window - input please

slimak,

That is a long link, if ever I saw one... Those mint look in great shape!

Here is an update:


 o
RE: CFL lamps near window - input please

hehe sorry about the long link :) just wanted to prove a point. Wow your mint is ready enough to make some mojitos ! :) how is the other one doing?


 o
RE: CFL lamps near window - input please

slimak,

It's been a little over 3 weeks for both plants. I'll likely be harvesting the spearmint at the 5 week line and maybe leaving the chocolate mint for another week after that. I'm curious to see if the plant will go to seed in these conditions.

The chocolate mint has been turned around to let the other side grow in. Hope this helps it.

Chocolate Mint:


 o
RE: CFL lamps near window - input please

This one looks great also :) I have to try grow some mint myself and see how it turns out. Did start off growing your mints from seed? Which variety tastes very minty?


 o
RE: CFL lamps near window - input please

slimak,

I just bought a perestablished plant in a small container. If you choose to grow mint you likely will only have success with spearmint, as mint seeds seem to like to default to spearmint for some reason.

The most minty tasting is peppermint, which has about 40% menthol. This is alot. A spoonful of dried chocolate mint chewed is enough to make ones mouth feel as if it was on fire from all the menthol. Spearmint has about 1% menthol, but is great for soups and addons that need not overpower ones pallet.

Today I harvested the spearmint. It's an okay amount considering it was grown indoors. The flavour does not seem as potent as the outdoor grown mint. I'd say it might have lost about %50 potency. This includes the chocolate mint as well. There seeems to be much less of a menthol taste.

I'll be just letting the plants grow from now on, harvesting only as required. I'm thinking this will help to hasten growth, especially root growth.

Spearmint Harvest:


 o
RE: CFL lamps near window - input please

I say it's quite a nice harvest you got there :)
I'll try a few varieties from seed and see if they taste different. I don't really use mint that much but I do like it and if I had it available all the time I'll probably get accustomed to it :)


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Growing under Lights Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here