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| This thread is created, and only for people who have used Lava rock as a growing media, wish to use Lava rock as a growing media, or are interested in using Lava rock as a growing media. No other replays will be tolerated. Any reference to hydroponic systems or anything other growing media other than Lava rock will be dealt with harshly. That's simply to make sure the thread does not GET SIDETRACKED, AND/OR BECOME OFF TOPIC.
Anyone else use Lava rock as growing media before? |
Follow-Up Postings:
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- Posted by TheMasterGardener1 none (My Page) on Sun, Feb 12, 12 at 13:02
| It tends to be a bit more expenisive then hydro-tone. But that could be a regional thing. |
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| Around here lava rock is dirt cheap and abundant, but it doesn't lend itself to small net pots. |
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| It's my understanding that lava rock needs to be washed thoroughly. I am wondering if anyone has had problems with pH using it. grizzman |
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| When I use net pots, I only use small ones. I haven't found a vegetable yet that requires more then a 2" net pot(I suspect corn might and possibly brussel sprouts). I can't speak to large multi-year plants but basically anything with a stalk 1/2" or so doesn't need a large pot. I tend to plant trees and berry bushes in the ground because I know at some point I'll be negligent of them. Oh! when using pots I've only used NFT and DWC. When I was growing the soy beans in EnF, I didn't use pots. In that case I did use lava rocks to fill the tray. I didn't really have any pH problems, but then the whole deer incident kept me from having a complete "season". They did a tremendous job of retaining moisture. I suspect, in that system, I could have watered them once a day and they'd have been fine, but it was a wet season that year. |
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| grizzman I have grown many (if not all my) tomato plants with stalks well over 1/2 inch wide. When talking about using 2 inch baskets, one thing that is extremely important (and makes a huge difference) is the type of system you are growing it in. In a DWC (Deep Water Culture) slang for "Water Culture" the roots have more root space than 2 square inches. Thus, it can be confusing for those that don't know how the type of system used will affect the plants growth/root system. Fact is if you have the right plant support, you don't need to use any baskets at all. In any hydroponic system, as well as if the water delivery system is run correctly, and the plant support system is designed right as well. But saying it dosen't need any root space at all (even just 2 inches) is untrue (same for saying the the smallest basket) in most contexts. |
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| I have used it before in a DWC setup with 8 inch net pots (5 gal buckets). This was an attempt at an organic set up..of sorts. The surface area of the lava rock would help provide an environment for beneficial bacteria to grow. Overall it worked well. Very hard to clean though, haunted by the red dust. Extremely hard to clean roots of off. My powerwasher just creates more red dust. I recommend the pebbles over the larger rocks. |
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| grizzman I know you mentioned that you use NFT and DWC systems, and that you were referring to those as your experience with regards to pot size. I probably would re-phrase my statement/reply, but cant edit the post. So I'll explain my thinking more here. For every post there are thousands of people that read them that aren't registered in the forum or even reply. 99% of them don't read many of the other threads (your past statements), thus don't understand the details that would make a difference. In that context I wanted to explain/clarify more that it depends a lot on the type of system used, how it was built, and how it functions and their specif growing conditions that make the biggest difference. Rather than just picking a size, and hoping it works for you because it works for someone else. I always prefer getting people to think about their system/system design, and the pro's and con's of it rather than just giving specific (do this) directions. artwk This is a great example of why I try to give pro's and con's, rather than specific (do this) directions. Even though you were utilizing the same type of system (DWC), because you were using organic methods, the larger amount of growing media served a valued purpose. That holds true for any system design (organic or not). It depends on the specifics of each persons situation, system, system design, environment, and even expectations. Did you have any pH issues using the lava rock? |
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| I'm just sharing an experience I have had, I am by no means an expert. This was about five years ago, and indoors. The red dust would tend to settle on the bottom of the buckets after some time. I do not remember ph problems. Can't really comment on the tds, as I never checked.
This is a first lady tomato clone about 2 weeks in. 8 inch pot, 1000 watts. I have several bags of the pebbles I will be using once springs rolls around for some pepper plants, outside ebb$flow. About cleaning, I accidentally let the roots rot in the rocks. It was some nasty stuff. |
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| Type of system is not actually important so much as available space for roots. you're correct, HH, in that no base support is required. I use 2" pots for support of smaller plants. a small pepper plant won't require any more support where as a tomato will but only as it gets larger. I never stated that all the roots would stay in the basket and knowing they won't is why you don't need anything larger. It is not my job to ensure everybody knows everything about growing plants (I don't know it all myself) If anybody is fool enough to read one post and act on it, well . . . a fool is as he does. It's not my job to ensure the world is without fools. Thats an unsurmountable task. Only a fool can remove his title. All that means is I respect people enough not to assume they're fools and unable to think for themselves. That's why my responses don't imply ignorance of the subject. |
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| I have never used Lava-Rock as a medium before, But I have filled my whole ebb and flow table this year with it. Got a super deal on some so why not? As far as PH.. Well I started with 6.1 and after 48hrs it went to 6.3 so not too bad at all. Though the rock I am using is LARGE I am hoping it will work out, but with what I paid for it it would be an easy replacement if not. Was going to use hydroton but at $300 to fill the bed VS $30 to fill the bed with lava it was WAY cheaper to use lava. I'll post a follow up in a month or so and let ya know how it works out. -Mus |
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| You might want to cover the top with something or else algea will start to grow near the moisture line, Well, unless they rock is substantially deeper than the water level is high. |
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- Posted by hardclay7a (My Page) on Sun, Feb 24, 13 at 17:22
| I've used both red and black lava in a home made DWC setup utilizing 18oz. plastic drinking cups drilled full of 3/8" holes for pots. I did have to modify some lids to fit as Grizzman sugests, but that was mostly due to evaporation loss problems. Algea & Ph didn't seem to be any more or less of an issue than other inert mediums such as pebbles, gravel or perlite. I did clean the lava between uses in a pressure cooker to remove dead root matter. It does create a gritty dust sedement in the bottom of reservoirs which may not be acceptable in many systems. However, it is very porous and roots cling to it quite well. ~Ken~ |
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- Posted by Cole_Robbie none (My Page) on Sun, Feb 24, 13 at 18:54
| Lava rock is fine as long as you don't move the net pot full of it very much. The sharp edges can crush a stem much more easily than hydroton. Also, if your system is making a vibration from the pump, the sharp lava rock can cut the stem. Otherwise, it's fine. Any ph-neutral rock will work. |
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| why not just use gravel like some do? its the cheapest by far |
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| Gravel is also very heavy. That is why I don't use it. Well and I have a bag of hydroton laying about. |
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- Posted by hardclay7a (My Page) on Tue, Feb 26, 13 at 10:57
| Yes Cole, Lava is very sharp and it may "wound" roots if vibrated or moved around a bunch. However most roots have a tendency to heal and branch out. If you've ever pruned roots you have experienced this first hand. Maybe dead root matter can cause Ph problems in some systems although I've never seen lava cut plants off at the stem. Yes Grizzman, Gravel is very heavy and not very porous. Lava is very light when dry and some pieces have a tendency to float untill soaked. Hydroton Is most probably a better medium. Lava in my neck of the woods is a good cheap medium. The only medium cheaper would be Red Hard Clay. Good Luck, ~Ken~ |
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| I really rigged a homemade lava rock hydroponic "tank". I took a plastic bin cut to about 6-8" tall, set a seed rack upside down to set Plastic baggies with slits I put in them to hold the lava rock and plants. Just the bottom o the baggie was in water and wool felt for a wick inside the baggie. I rinsed the lava rock first to get the dust off before planting and have no idea what the pH was. I told you this was crude at best but works great. |
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