correct height above plants hps 150w ?

15 years ago

Can anyone give me the correct height for an hps 150w with reflector? I also have 3 sides of the growing area covered with reflective material. I currently have just moved one flat of lettuce under the hps light at 14 inches to the soil or about 12.5 inches from the top of the leaves. I suppliment the light with one 24 inch flourescent on the side of the wall about 6 inches from the top. I have to rotate the flat daily to take advantage of the additional light. The lettuce flat will be replaced soon to sprout tomatoes. Advice, especially on the distance between the 150w hps and the top of any leaves?

Thank you,

~tom

Sort by:Oldest

Comments (12)

hautions11
15 years ago
tom I keep a 400w HPS about 12 inches from our plants. Less then that for a 150 would be fine. I am guessing here, but 6-8 inches would probably be good.
wordwiz
15 years ago
I like to have at least 3500 lumens reaching the plant canopy for seedlings. If your bulb is rated at 15,000 lumens, at two feet away you should get about half that which is more than enough. (My opinion)

Mike
Related Discussions
How to Choose Correct Container Size for Different Plants
Q
Comments (13)
Ellen & Jenn - A copy/paste job from a reply I wrote on another thread: How large a container can or should be, depends on the relationship between the mass of the plant material you are working with and your choice of soil. We often concern ourselves with "over-potting" (using a container that is too large), but "over-potting" is a term that arises from a lack of a basic understanding about the relationship we will look at, which logically determines appropriate container size. It's often parroted that you should only move up one container size when "potting-up". The reasoning is, that when potting up to a container more than one size larger, the soil will remain wet too long and cause root rot issues, but it is the size/mass of the plant material you are working with, and the physical properties of the soil you choose that determines both the upper & lower limits of appropriate container size - not a formulaic upward progression of container sizes. In many cases, after root pruning a plant, it may even be appropriate to step down a container size or two, but as you will see, that also depends on the physical properties of the soil you choose. Plants grown in slow (slow-draining/water-retentive) soils need to be grown in containers with smaller soil volumes so that the plant can use water quickly, allowing air to return to the soil before root issues beyond impaired root function/metabolism become a limiting factor. We know that the anaerobic (airless) conditions that accompany soggy soils quickly kill fine roots and impair root function/metabolism. We also know smaller soil volumes and the root constriction that accompany them cause plants to both extend branches and gain o/a mass much more slowly - a bane if rapid growth is the goal - a boon if growth restriction and a compact plant are what you have your sights set on. Conversely, rampant growth can be had by growing in very large containers and in very fast soils where frequent watering and fertilizing is required - so it's not that plants rebel at being potted into very large containers per se, but rather, they rebel at being potted into very large containers with a soil that is too slow and water-retentive. This is a key point. We know that there is an inverse relationship between soil particle size and the height of the perched water table (PWT) in containers. As particle size increases, the height of the PWT decreases, until at about a particle size of just under 1/8 inch, soils will no longer hold perched water. If there is no perched water, the soil is ALWAYS well aerated, even when the soil is at container capacity (fully saturated). So, if you aim for a soil (like the gritty mix) composed primarily of particles larger than 1/16", there is no upper limit to container size, other than what you can practically manage. The lower size limit will be determined by the soil volume's ability to allow room for roots to 'run' and to furnish water enough to sustain the plant between irrigations. Bearing heavily on this ability is the ratio of fine roots to coarse roots. It takes a minimum amount of fine rootage to support the canopy under high water demand. If the container is full of large roots, there may not be room for a sufficient volume of the fine roots that do all the water/nutrient delivery work and the coarse roots, too. You can grow a very large plant in a very small container if the roots have been well managed and the lion's share of the rootage is fine. You can also grow very small plants, even seedlings, in very large containers if the soil is fast (free-draining and well-aerated) enough that the soil holds no, or very little perched water. I have just offered clear illustration that the oft repeated advice to 'only pot up one size at a time', only applies when using heavy, water-retentive soils. Those using well-aerated soils are not bound by the same restrictions. AL
...See More
Correct or Incorrect - Watering till it drains
Q
Comments (17)
How's it going, Matt? Can I make clear first, that I didn't say "... perlite doesn't improve aeration and drainage". What I said was, "Perlite isn't equally effective at increasing the two directly related properties of drainage and aeration in all soils. Strangely enough, the closer the soil is to not needing perlite at all, the better the perlite is at increasing those properties", and then I went on to describe why that is true. It's not at all that I don't recommend it, it's a standard part of the pine bark-based 5:1:1 mix that so many at GW use. Why? ... because it improves aeration and drainage in that soil. If little kids were making mud pies, would mixing perlite into the mud make it lose its tightly held water (another pudding analogy)? The answer is 'NO'. Why then should we expect perlite to rescue us from an already sludgy soil? The message I was trying to deliver is sort of 'You can't make diamonds out of dog poop'. ;o) If you start with a highly water-retentive soil (sludge) and add perlite to it, you don't suddenly have a good, serviceable soil, you have sludge with perlite in it. I sort of outlined the reasons why perlite is effective when it is, and why it's not when it's not, so I won't go over that again. I think my message would be best described as an encouragement to take a close look at your soil before you use it & try to decide if it is going to fill the needs of the plant; most importantly, will it retain good aeration and drainage properties for the intended life of the soil. Because most hobbyists leave their plants in the same soil far, far too long, the answer, when using a peat-based soil is usually a resounding 'NO'. I'll offer my thoughts on growers that can't/won't make their own soils or can't/won't go to the extra effort of watering a little more frequently. I'm not being accusatory, just making basic observations. Growing plants well is an investment in time and effort. First, we need to arm ourselves with knowledge, then, we need to put forth the time and effort to provide cultural conditions our plants approve of. If we can't/won't, then we shouldn't expect perfect plants & should be willing to live with the fruits of our labors or lack thereof, or just be frustrated with our plants. Our kids don't grow up to be good human beings w/o some time and attention from their caretakers. If you can't/won't make the effort to work out, or you can't/won't diet, you'll likely have to deal with consequences. Time and effort in, affects what we get out, across a wide spectrum in our lives, and plant husbandry can't be excepted. I can't decide the middle ground for anyone, Matt. I do know that if readers would at least make the effort to acquire some pine bark in a suitable size, a bag of perlite, and a little lime, they could easily build a soil, still using the bagged stuff as a part of it, that would be far superior to a peat blend. Some won't believe it will make a difference, but there are literally thousands of posts to the contrary right here on GW that point to a striking improvement in the grower's ability to keep their plants happy after changing to a well-aerated and structurally stable soil. Others won't make the effort, and that's fine - we all have to establish our own priorities and I understand that. Others will lean the other way. They'll even be very willing to make the effort to run down ingredients for even better soils, like the gritty mix. We're all different. I can help with some of the information needed for people to make up their own minds on the soil thing, but without considerable knowledge of an individual's priorities, I can't help much with establishing the middle ground - we're just too varied. Al
...See More
Briggs 26hp Intek problem
Q
Comments (27)
Hi All, Got the new cylinder head. It does look like Briggs did something different with the valve guides. Not sure what. Anyway here are a few picture for those of you that keep getting bent pushrods or blown head gaskets which can cause nasty problems (oil consumption ?) . Maybe these pictures will help show you what might be causing the problem. Picture #1 here is a close up shot of the #1 cylinder head exhaust port with a red text note of the position of the exhaust valve guide. http://photos.gardenweb.com/garden/galleries/2007/10/bad_briggs_cylinder_head.html?cat=tractors_lawn_equipment Picture #2 here is a close up shot of the #1 cylinder head exhaust port with a red text note of the position of the exhaust valve guide. This shot is about top of cylinder casting level with a couple of notes. Note the valve guide is about 1/8 to 1/4 inch above the cylinder head casting top. This causes the valve not to open completely. When the valve can not open completely then something has to give which is the push rod. Once the push rod bends it is more likely to fall out. When it falls out the valve will not open at all so when the #1 piston fires something has to give. That something is the head gasket. When the head gasket gives it has a pretty good chance of giving out at the section between the push rod sump and the piston. When this happens the cylinder will suck (and burn) a lot of oil. http://photos.gardenweb.com/garden/galleries/2007/10/bad_briggs_cylinder_head_2.html?cat=tractors_lawn_equipment Picture #3 here is a close up shot of a NEW #1 cylinder head exhaust port with a red text note of the position of the exhaust valve guide. Note that is that guide is where it is suppose to be which is really close to the entry point of the valve stem. http://photos.gardenweb.com/garden/galleries/2007/10/new_briggs_cylinder_head_exhau.html?cat=tractors_lawn_equipment And finally last picture is of the old and new cylinder heads. If you look closely you can see the difference in the height of the valve guides between the two heads. http://photos.gardenweb.com/garden/galleries/2007/10/old_and_new_cylinder_head.html?cat=tractors_lawn_equipment I am hoping that this will help people identify a possible problem with their engine. Later, Tom :)
...See More
HPS lights vs Fluorescents
Q
Comments (15)
Hi Like mike I use a conversion bulb, works just fine for me too. All that humping boxes in and out sounds oh so familiar to me..LOL...I used to do a lot of that. "If I start growin in January and get one 400 watt hps how many plants do you think I can grow big. do you think that is better than twice the number of small plants." Thats depends on what you mean by big!!! If its just for say twelve inch plants to go outside, the 400 watts will cover effectively ten st ft maximum in theory. I use mine however over a larger area of about 15ft sq (3' x 5'), an oblong with shade lovers furthest from the light in back (pubescens, tepins etc). The results have always been fine for me. I can fit about a hundred (4"-6") pots in there and have benn known to practise a two shifts of 12 hrs system, but thats just like lumping boxes in and out again. The 12 hrs is not enough continuous light per day for best growth of the plants either. If you are wanting to grow plants and mature fruit indoors you will get a lot less plants under the lamp perhaps six to eight would be OK. If you can plant out early June then I guess its best to start in January, for chinenses and baccatums in any case..perhaps the pubescens a bit earlier still and annuums in the first half of February. It depends what you want to grow. All the best Guy
...See More
tom_n_6bzone
Original Author
15 years ago
wow, what a divergence of spread on the distance?! So, is is closer to 6-8 inches or is it closer to 2 feet?
~tom
tom_n_6bzone
Original Author
15 years ago
so, I take the first messages ave of 7 inches and the 2nd posters first posters figure of 24 inches and add them together for 31 inches. the average is 15.5 inches.
~tom
hautions11
15 years ago
Tom, I believe the discrepancy comes from the plant you are growing. For new seedlings wordwiz is probably right in the fact you do not want to over do it. Once a couple sets of true leaves are there etc, 6-8 inches on the light lovers like tomatoes. Don't burn your new delicate seedlings is the answer. Hope that helps,

Larry
wordwiz
15 years ago
Tom,

I just ordered a couple of 150 watt lamps so I should have them by Friday (keeping fingers crossed). Once I get them hooked up I'll give you a light meter reading.

From my experiences, (and if you don't include the heat factor), the only lights you have to worry about getting to close are high power LEDs if the plants are not use it it. I stuck flat of tomato plants that had been under a 14-watt panel ll of their two weeks of life about five inches away from a 45-watt panel - they did not like it at all!

One other consideration - do you need to maximize the coverage area or not? I'm growing a lot of plants and trying not to spend more than necessary on equipment and power while still growing healthy plants. Last year, 3500 lumens at the plant canopy worked great. This year, I'm shooting for 4,500-5,500 if possible.

Mike
tom_n_6bzone
Original Author
15 years ago
Thanks guys. I don't need to maximize the area. I have one place for a flat that I'm using the 150w hps with a side mounted flourescent. My other areas have flourescents only. I look forward to your readings Mike!
~tom
wordwiz
15 years ago
Tom,

They are impressive. At a distance of about 16", I'm getting 30,000 lux directly under the light. If I go to the edge of what I consider the coverage area, I'm still getting 9,000 lux. So your original thesis of 15.5 inches will bathe your plants in light.

For the fun of it, I measured the lux at 8" directly under the light - I was getting about 80,000.

All I have under the light at the present time is a tray of Bhut Jolokia and a tray of Red Savina seedlings that are less than 1.5" tall.

I'll be following the plants' growth to see how they respond. Keep in mind, my goal is to transplant them into small containers to sell so a little little extra bit of stem won't hurt.

HTH,

Mike
tom_n_6bzone
Original Author
15 years ago
that is impressive Mike! Now, if the same hps lamp could be replaced with a 150 watt MH that is also 150 watt, ED17 and a medium base, it would be perfect!

Thank you,
~tom
wordwiz
15 years ago
Tom,

I may have to join a pot forum to get an answer! The light is a different color, something like an yellowish orange. Using my not so reliable spectrometer (a CD laying at an angle with the light reflecting it through a very small slit at the other end, it appears to be mostly yellow, red and green with just a trace of blue. As long as they do not get too leggy, I'm fine.

Mike
wordwiz
15 years ago
Tom,

Finally found the right search terms for Google. Yes, I can use the fixture and switch to a MH bulb. That's the good news. The bad news is I have to use a MH conversion bulb and most of them run at about $90. I did find one place that was having a sale - $40 per bulb.

Mike
tom_n_6bzone
Original Author
15 years ago
Thanks Mike, The price of the conversion bulb is too much for me, so I'll just supplement the hps with flourescents when I need it. or start with flourescents and end with hps. I started leaf lettuces in a flat under flourescents but after 10 days and they weren't doing that great. After moving them under the hps, they took off like weeds and they are not leggy. It's only been 5 days with the hps. I can't wait to try a flat of tomatoes next!
~tom

correct height above plants hps 150w ?

Comments (12)

hautions11

wordwiz

Related Discussions

tom_n_6bzone
Original Author

tom_n_6bzone
Original Author

hautions11

wordwiz

tom_n_6bzone
Original Author

wordwiz

tom_n_6bzone
Original Author

wordwiz

wordwiz

tom_n_6bzone
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

correct height above plants hps 150w ?

Comments (12)

hautions11

wordwiz

Related Discussions

tom_n_6bzoneOriginal Author

tom_n_6bzoneOriginal Author

hautions11

wordwiz

tom_n_6bzoneOriginal Author

wordwiz

tom_n_6bzoneOriginal Author

wordwiz

wordwiz

tom_n_6bzoneOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

tom_n_6bzone
Original Author

tom_n_6bzone
Original Author

tom_n_6bzone
Original Author

tom_n_6bzone
Original Author

tom_n_6bzone
Original Author