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semi-hydro compared to gritty mix

Posted by greentoe357 7b NYC under lights (My Page) on
Fri, Feb 7, 14 at 0:08

As somebody who has been growing hoyas in "gritty mix" (pine bark, turface or calcined DE and granite grit; pictured), what am I missing, if anything, by not going semi-hydro for at least some of my hoyas and maybe other plants?

I've read/seen very positive reviews of semi-hydro method, but with gritty mix, I am kind of largely there already - very good aeration, instant drainage, but with some water retention in the mix. There is no pool of water to wick up from though - roots just get the water+nutrients from retained water like in traditional pots, but you know, minus the suffocation.

So, I am interested particularly in stories/opinions of those who tried both s-h and gritty mix.

It can get pretty dry here in the winter - I may not be able to water enough in semi-hydro. How often do you water indoors with central heating on?

I posted a more general s-h questions here (http://forums2.gardenweb.com/forums/load/houseplt/msg0203092013139.html), but I want to get hoya crowd's opinions in particular. Thanks.


Follow-Up Postings:

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RE: semi-hydro compared to gritty mix

I don't use your type of gritty mix, but I do use a mix of Turface MVP and Perlite, which probably behaves similar. I also have other Hoyas in S/H.

They way I choose which potting method is, if a Hoya prefers to be evenly moist, it gets put into S/H. If not, it gets put in the Turface mix. Although I do have exceptions.

Both work fine for me.

I do want to mention there are some basic rules to follow in order to use S/H successfully.

Main ones are existing roots sometimes don't adjust. Starting in S/H from a cutting seems to give better results.

And fertilizing, and fertilizer strength and flushing the pots(related to fertilizing) are more important to watch with this method.

Also, there are many orchid people that use S/H for plants that do like to dry out and they seem to be successful. I just prefer to not.

I have one plant in S/H in a cut down milk gallon as its pot. Silly thing has overtaken the space with its roots and I will have to up pot it soon to a bucket. It is a multiflora, that I prune twice a year because it grows too fast for me to contain it.

If you decide to try it and have questions, feel free to email me.

Renee


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RE: semi-hydro compared to gritty mix

They way I choose which potting method is, if a Hoya prefers to be evenly moist, it gets put into S/H. If not, it gets put in the Turface mix. Although I do have exceptions.

Interesting. My understanding from others is the top layer of s-h media does dry out pretty fast unless in tropical environment. Doug in Vermont and others say to water s-h daily if not twice a day in relatively dry climates. Although I think you are in Florida (are you?), so your experience may be different.


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RE: semi-hydro compared to gritty mix

I have no idea how Doug in Vermont or the others you mention does his/their S/H, so I cannot comment on that. But if you are having to water (and water is wrong for this method, it should be a weak fertilizer solution) every or twice a day with this method, something is not right.

Also I'm not sure why the top layer drying out has to do with plants that like to be evenly moist, or am I not reading that correctly?

As for the top layer drying out, it is not preferred, and if you are doing S/H correctly, it shouldn't happen or be minimal. But it is not the worst thing that could happen either, sometimes you will get fertilizer build up on the top layer, if it keeps drying out.

Humidity is only one factor in evaporation rate. Yes I live in Florida, but during the dry season, it has gotten pretty dry here. My plants in S/H are fine. Actually they are more than fine, they grow like weeds and bloom.

Renee


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RE: semi-hydro compared to gritty mix

What works for one person may or may not work for someone else. I can only report that I have phenomenal success with many Hoyas watering them once per day in semi-hydro. H. praetorii, H. davidcummingii, and H. megalantha are almost never without flowers when treated this way. I will be blooming H. inflata any day now only eight months after starting from cutting watering with nutrients everyday. I have attached a photo of the growing buds on the bottom of this post.

If anyone had the resources, and necessary space, I think a many Hoyas could be flowered in even less time using a real ebb and flow full on hydroponics system. The pots would have no reservoir and the media would be flooded 3-4 times per day. Most any crop from Tomatoes to Marijuana grow many times faster this way, and I'm sure Hoyas would as well.

Doug


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RE: semi-hydro compared to gritty mix

Wow!!H. inflata is beautiful...Nice growing Doug!I havent had too much luck growing in s.h.H. davidcummingii had been in growstones for about 9 mnths and no new growth.I prob dont give it enough fertlizer.What rate do fertlize with yours?Have you been having good results with growstones and s.h.?


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RE: semi-hydro compared to gritty mix

I've tried semi-hydro (hydroton) with mixed results. Most seemed to do okay for a while, but then died. Must be doing something wrong.


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RE: semi-hydro compared to gritty mix

Doug, you write you do water everyday, but greentoe wrote that you said you have to water everyday. This is two different things.

Do you feel that every day is absolutely needed?

I'm curious as I don't. I change the solution depending on when it is needed.

Renee


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RE: semi-hydro compared to gritty mix

Renee,

You are correct; those are two different things.

Watering every day in S-H is absolutely necessary when a Hoya has completely filled its container with roots and has a large leaf canopy. At that point watering once or even twice a day may not be enough.

I choose to water often, because deep down I guess I don't completely trust the wicking capability of the medium. I also think that fresh oxygenated nutrient solution flowing over the root structure spurs on growth. I also never bother to flush the medium with fresh water, as I am flushing every time I water with nutrients. I always water until water pours out of the holes above the reservoir.

What I do works for me, because it is warm in the grow tents that I use. I would not water nearly as often if it were cool. I have active growth all year round with the equivalent of 365 days of sun in these growth chambers.

I also have to say that I grow less than 5% of my Hoyas in semi-hydro. The majority of my plants grow in a chunky loose potting mix. To grow more in s-h, would be untenable for me growing inside as I do.

Doug


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RE: semi-hydro compared to gritty mix

Also I'm not sure why the top layer drying out has to do with plants that like to be evenly moist, or am I not reading that correctly?

By that I meant that if there is a level of substrate (the top level) that dries out relatively quickly, then all the roots are not evenly moist by definition.

As for the top layer drying out, it is not preferred, and if you are doing S/H correctly, it shouldn't happen or be minimal.

"Be minimal" maybe, but it does happen. Ray, the inventor of semi-hydro method, writes about why and how it happens here: http://www.first rays.com/dry_line.htm.

(Ugh, GardenWeb does not allow links to his site - copy and paste into the browser, remove the space in the link and press Enter to go there).

Generally, his website is great for detailed learning about semi-hydro. I am still going through it.

I can only report that I have phenomenal success with many Hoyas watering them once per day in semi-hydro.

In winter in your house outside of a grow tent? (Not doubting at all, just asking, because I know you grow some things in grow tents in the winter.)

Those blooms are the most adorable thing ever, by the way!

Have you been having good results with growstones and s.h.?

I was wondering about Growstone as s-h media as well. Rough volcanic-looking non-shiny surface and non-round uneven shape all theoretically tell me the medium is very interesting - wicking may be better because of more points of contact between the particles, and water retention may be higher because of the rough surface.

Ray writes in detail about his experiments comparing media here (http://www.first rays.com/PrimeAgra/compare.htm again, remove the space). Capillary action part of the experiment especially blew my mind. Growstone was not included in his experiment though. Separately he wrote that Growstone is on the alkaline side, which orchids do not prefer (he's an orchid guy, I am not sure what alkalinity hoyas generally like). Also, Growstone is very light, to the point of potentially not being able to support taller heavier plants.

I personally would be very interested in Growstone capillary action experiment (very simple the way he did it, and makes sense), but I do not have Growstone or actually any other s-h medium on hand. If anybody can do the experiment and report the results, that'd be great.

I've tried semi-hydro (hydroton) with mixed results. Most seemed to do okay for a while, but then died. Must be doing something wrong.

Any guesses why, restoner? Did you fertilze weakly daily? How did the plants die - dry up or rot or what? What kinds of plants? How humid/dry was your environment?

Ray writes that the correct way to water s-h is to quickly flood the whole pot with weak fertilizer solution to the top and let it drain out. This is obviously very different from what people do in non-semi-hydro, where the best way is to water with gentle spray, let it absorb for a few minutes or even 10-20 minutes, then water gently all over the surface again till it drains freely from the bottom. So, if you gave a semi-hydro pot a gentle spray, maybe not the whole medium was wetted?

Doug, you write you do water everyday, but greentoe wrote that you said you have to water everyday. This is two different things.
Do you feel that every day is absolutely needed?

I'm curious as I don't.

Doug will hopefully reply, meanwhile here are some of the things he wrote on the topic of semi-hydro: http://vermonthoyascom.fatcow.com/?s=semi-hydro. Some may be outdated because the method grew on him over time, he said.

Renee, you may feel you do not need to water every day because of your climate. I hear you on the drier winter, but still, growing in Vermont or in my centrally heated New York City apartment is gonna look very different. My humidifier is huffing and puffing as we speak, and it only raises humidity maybe 5-10% at most in my circumstances. When the starting point is humidity in the twenties% for months, the medium will dry out faster.

I change the solution depending on when it is needed.

How? Very interesting.


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RE: semi-hydro compared to gritty mix

Jimmy, I'm glad you like my inflata! I wanted that plant for two years, before I was able to obtain one. A big shout of thanks to Julie Kennedy in the U.K. for making it possible!

I am LOVING growstones, and I have you to thank for it. I first heard about them from one of your posts in another forum! As a testament to their effectiveness the inflata above is growing in them.

I'm a bad one to ask about fertilizer rates, as I am far from exact. In the winter I use a heaping teaspoon of MSG fertilizer mixed with 3 gallons of water with every watering. This rate is only applied to actively growing plants in my tents. The plants in the regular house get roughly half that rate of food. In the summer, when everything is actively growing, I will double the amount of plant food to around a tablespoon mixed with 3 gallons of water.

I'm sure that your davidcummingii will take off this summer with all of your warmth and humidity.

Restoner, the first time I tried s-h I was very disappointed as well and threw out most of my plants that were growing in it. I also don't think that all Hoyas will do well in s-h, or at least it is not practical for many. Some Hoyas however seem to grow best in it. So don't give up!

Doug


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RE: semi-hydro compared to gritty mix

Thanks for all the good info Doug" Im my case,its prob a combo of both water and nutrients.I water it every few days(3) sometimes with nutrients sometimes just plain water.The humidity in my apt is from the mid 20's to mid 40's depending on how much the heater runs.My humidifer is pumping out about 3 gallons of water per 8 hours,but it really helps the plants from die back and drying up.Glad you gave a thumbs up for the growstones!I have a 2cubic ft bag I got on Amazon for 40$!They have a new product with the stones and some coco fiber that looks interesting.Im gonna try to make my own with the fiber.looks like a half and half mix.My hope is that it will get evenly wet when watered .Its somewhat a task to get the mix i have now totally wet in the winter months without holding each plant over the sink(growstones ,bark,coco chips,bit if potting mix.)When some of the bark or coco chips gets bone dry, water beads around it and right through the bottom of the pot.This wont be a prob in summer,but the dryer conditions in winter can lead to this.Maybe the finer fiber and growstones will make it easier for the water to penatrate the entire medium.Im gonna try it and see.Thanks again for all the s.h. tips!ps.... Post a pic if inflata when it opens!


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RE: semi-hydro compared to gritty mix

Greentoe,

I looked at all of First Rays experiments, and like you was especially fascinated at the capillary action of PrimeAgra. I have used PrimeAgra for some time now, and I have to say that while I do not use crystal clear containers, I have never seen the surface of the media look wet like in his experiments. If the surface looked wet like that maybe I would not be watering nearly as often. The surface of my media looks dry a couple of hours after watering.

The only reason I can think of that would cause the surface to look wet like that is that he started with a glass with far more water in it than is recommended for s-h. It is also interesting to see some photos of Orchids growing in pots with a water level far higher than the one inch up from the bottom that he recommends. Look at the photo of the Orchids in s-h pots on the bottom heat page. It looks like the water level is 2 1/2 to 3 inches high on the pots. I have never tried s-h with a water level that high - maybe it would work better; I just don't know.


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RE: semi-hydro compared to gritty mix

I am LOVING growstones.
I have used PrimeAgra for some time now [...] I have never seen the surface of the media look wet like in his experiments.

Is Growstone then your favorite semi-hydro medium, Doug? Do you like s-h indoors outside of grow tents as well, or only in high humidity tents?

The only reason I can think of that would cause the surface to look wet like that is that he started with a glass with far more water in it than is recommended for s-h.

Well, he SAYS in the description of the experiment that he started with 60 ml of water in both cups. No reason to think he's lying, but he does sell PrimeAgra, so of course one has to be skeptical.

Another reason for such results may be that PrimeAgra was more saturated than the other medium to begin with. No malicious intent is necessary - if he dried both mediums the same way, then the medium that gives off water vapors less easily will still be more saturated at the start of the experiment. Interestingly, Ray is a ceramics engineer, so he has to know all these things and more backwards and forwards.

I have a terrible itch to replicate this experiment once I get my sweaty little hands on at least a cap full of different media. - UNLESS someone who already has several kinds of media is interested in trying.

It is also interesting to see some photos of Orchids growing in pots with a water level far higher than the one inch up from the bottom that he recommends. Look at the photo of the Orchids in s-h pots on the bottom heat page. It looks like the water level is 2 1/2 to 3 inches high on the pots.

Those plants are orchid babies, so the pots likely are smaller than the most common 32 oz container. The water level seems about three stones high - that could be an inch.


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RE: semi-hydro compared to gritty mix

All of my S-H plants are growing in high humidity tents. I've used it before in the dry environment of the regular house in the winter and the plants just sit there in dormancy.

I have five plants in Growstones using s-h right now. Four are thriving and one is doing nothing. While I'm very impressed with Growstones, I have also had very good luck with PrimeAgra having flowered the following plants with it; praetorii, lasiantha, davidcummingii, samoensis, dolichosparte, lacunosa, and linearis.

I will probably keep using both, but right now I'm liking the Growstones and may start incorporating them into my potting mix.

Doug


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RE: semi-hydro compared to gritty mix

I grow my s/h in s/h pots with the little meters that tell you when to water. So the roots sit in the water at the level indicated by the meters. And most of those I grow are happy, and I only have to add water when they meter indicates, which is rarely more than once a week. I've had them become completely dry and they don't seem to suffer much at all. I'd grow more this way, but it's pretty expensive. Most of mine grow in 2/3 coir and 1/3 perlite.

Denise in Omaha


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RE: semi-hydro compared to gritty mix

I am getting a bag of Growstones, so there is some experimenting in my future.

Doug, if you are thinking of adding Growstones to your potting mix, note that they have 2 grades / particle sizes. The hydroponics substrate is larger particles, and what they call "soil aerator" is smaller particles. Does not mean you have to use the latter, of course. And you probably knew all this, but I thought I'd mention just in case.

And by the way, doesn't your mix already have like 7 ingredients? :-) What about the law of diminishing returns? (I am only partially serious. But that part is not zero. :-)


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RE: semi-hydro compared to gritty mix

Denise, sorry, forgot to reply to your post for some reason.

Those semi-hydro setups with meters sound interesting. What do the meters actually measure - water level in the reservoir? Or humidity somewhere in the container?

>> I've had them become completely dry and they don't seem to suffer much at all.

I wonder, when the medium looks dry on the top and walls if they are see-through, it may still retain enough water inside the pot and inside the medium particles, in order to give it off to the roots. So looks may be misleading here indeed. No harm in watering often because of all that air in-between the particles, but it may not be necessary to water that often, like you said.

If Growstones are used, supposedly roots will grow into the particles rather than around like with hydroton and PrimeAgra and other LECA substrates. And I guess that water inside the rocks is then even more readily available to the roots, yet still invisible to the eye.

Interesting.


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RE: semi-hydro compared to gritty mix

Greentoe, I'm not married to my potting mix. I'm always experimenting with it. As long as it remains a light chunk mix, feel free to throw what ever you want into it! I'm thinking that growstones might be a good substitute for some or possibly all of the perlite as it would not break down into finer particles the way that perlite does over time.

Thanks for explaining the difference between the two grades of growstones. I knew that there were two grades, but I could not ascertain the difference from reading their site. The soil aerator might be a better choice, as the particles are not quite so large - also it is a little cheaper.

Denise, I've always wanted to try the semi-hydro containers with the little water level indicators, but have not yet had a chance. They sound like a really nice setup except for the price.

Here is a photo of inflata now that it has opened:


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RE: semi-hydro compared to gritty mix

What a perfect lily-of-the-valley kind of flower! Beautiful.

>> I'm thinking that growstones might be a good substitute for some or possibly all of the perlite as it would not break down into finer particles the way that perlite does over time.

Good thinking. Growstones have more water retention and air retention capacity than perlite (or peat, for that matter). So, you might find you do not need to water as often - but can if you want to.

However, any time a mix contains both larger and much smaller particles, I am not sure how much we can rely on characteristics of larger particles, like Growstones in this case. Peat and other small particles will eventually get into the large pores of growstones, in-between the growstones and sink down to the bottom, and all three of these will affect water- and air-holding capacities of the mix, negatively and I would think significantly. No proof to back it up, but it makes sense when I try to visualize what's happening in the pots over time.

I have another semi-hydro question, Doug. Somewhere on your site you said repotting semi-hydro setup into a larger pot is more difficult than with more traditional chunky mixes. Is it because roots cling to particles stronger and so it's more difficult to remove or wash off the old medium?


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RE: semi-hydro compared to gritty mix

Doug, that inflata flower is just adorable! Are the individual flowers large?

GT, somehow, I assumed when you were talking about "growstones" you were referring to the hydroton - I probably skimmed past something that may have alluded to what you were really talking about. Interestingly, I was at our local home/garden show this last weekend (manning a booth for my cactus club) and Paradigm Gardens was there with a booth nearby. I spent a lot of time talking to them about growing media and they told me and showed me this new "growstones" product. I didn't remember that's what it was called, but I was fascinated by the fact that it was recycled glass, which doesn't sound at all like it would be something one would grow plants in. Nonetheless, he talked about how mixing it in with your current media will rid you of those annoying soil gnats. I may try a bag of the larger stuff to replace my perlite - it is, however, expensive!!!

Denise in Omaha


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RE: semi-hydro compared to gritty mix

Denise, check out this video: http://www.youtube.com/watch?v=pUPsIpd9TmQ. It's salesy, but there is an interesting water absorption demo at 1:10 with growstones vs hydroton. It does not behave as glass, I agree.

By the way, the demo has a flaw and causes at least one question. I wonder if they washed that hydroton before it gave off that red dust. I bet they didn't. And even if they did, for our semi-hydro application, you'll just wash the dirty effluent off, no big deal, it does not get pumped back into the more closed-end fully-hydroponic system forever.

And the flaw is: note how he places the Growstone largest flat face down. The soaking surface is way bigger - of course it's gonna soak up more water! It's water retention capacity per volume unit in the mix that matters. Now, maybe Growstone absorbs more water by that measure as well, but that is not what is being demonstrated.

And another thing I can think of: what if hydroton just needs more time to soak the water up? The plant is not in a rush! Need to measure after some time has passed.

>> it is, however, expensive!!!

I just bought 1.25 cu ft of the larger Growstones for $22, and Doug says smaller particles are cheaper. Checking large grade perlite (Espoma), it is $15 or so per cu ft., so perhaps the difference is not that large. Delivery fees may change this comparison significantly, of course. If you can buy one locally but not the other, it changes things.

As a side note, to rationalize the Growstone purchase and to lower delivery fee, I also bought another 4-bulb 4-foot fluorescent grow light. So, let's see, start with wanting to do a dinky little experiment on semi-hydro, end up paying $137. Yeah, sounds about right. :-/

This post was edited by greentoe357 on Wed, Feb 19, 14 at 13:06


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RE: semi-hydro compared to gritty mix

Denise, Each inflata flower is around 3/4 inch in diameter.

Greentoe, The longest I have had a plant do well in s-h is 2 years. That was davidcummingii and after that it crapped out. It was a solid mass of roots, which would have been difficult to transplant. It was easier to just take a cutting and start over. I mostly use 32 oz plastic containers to do s-h in and to move up to the next size container and fill in around the sides with more rocks just doesn't seem worth it to me. If one were to do it, the container should remain the same height as the original so the roots used to remaining in water would still be in water.

Unlike growing in soil, with semi-hydro I wouldn't think that you could really over pot a cutting. If I was going to grow something big like a macgillivrayi in S-H, I think I would start with a large container instead of trying to pot up from a small container. This is only my thought, and maybe others have more experience with potting up while using S-H.

Doug


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RE: semi-hydro compared to gritty mix

Doug, my javanica (wrote multiflora above, that was incorrect) I wrote about on my blog in June 2012, has been in S/H since I first got it. So roughly since spring of 2011. That is the longest for me I think.

And i up pot S/H plants whenever they need it, basically when the roots have completely taken over the pot. Just pull it out of the old pot, put it in the new pot, and fill in with LECA. Your comment about keeping the water level the same is a good comment, although for me, I just get close enough sometimes.

FYI both of my heuskaliana (this is so spelled wrong) are in constant bloom, once they started blooming, in S/H. Another one to try if you are interested.

Other Hoyas that I have growing well in S/H are retusa, memoria, buotii, blash... Sorry too cold to go out and look up the spellings right now. Have had others do well in it also, just as testing,but I got rid of most of my duplicate plants before I moved the last time.

And I start most cuttings in it as well.

Renee


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RE: semi-hydro compared to gritty mix

That is very good and useful information Renee. Seeing your list reminded me that I have also grown memoria in S-H and it has done far better than in soil. It is also very good to know that it is not that hard to pot up using S-H.

I should also mention a couple Hoyas that did not do that well for me in semi-hydro. H. elliptica does far better for me in regular potting mix, and I also tried magnifica, and it bombed in s-h as well.

Doug


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RE: semi-hydro compared to gritty mix

It's on! Gritty mix (which I normally use for all my hoyas and almost all other plants) vs. growstones semi-hydro with Hoya DS-70 and Dischidia ruscifolia. Planted today. I'll let you know how it goes from here.


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RE: semi-hydro compared to gritty mix

Hi Everyone,
I am sure a lot of you know already that I grow all my hoyas S/H.Over the years I have tired most of the different mediums there is.But S/H is the best for my growing needs.I love to take long vacations and this is by far the easiest for me to get a family member to water with out the fear of root rot.And most of my winter hoya deaths are down to just one or two,where as before had to re root a lot every winter.
Good luck to you Greentoe,I am sure you will do well.


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RE: semi-hydro compared to gritty mix

> S/H is the best for my growing needs.I love to take long vacations and this is by far the easiest for me to get a family member to water with out the fear of root rot.

My usual mix ("gritty mix") is very chunky and well-draining, so the chance of root rot there is also practically zero - unless there is standing water in the saucer, perhaps. (Although I do leave some water in most saucers for humidity and because most plants do soak it up within a few hours to maybe half a day.) I water freely even in winter. People who use gritty mix say it is much closer in how it works to semi-hydro than to traditional potting mix, even when it's well-draining. So, I do not expect very dramatic difference in my experiment, but we'll see, of course.


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