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- - Some beginner questions about S/H (http://www.orchidboard.com/community/semi-hydroponic-culture/102339-beginner-questions.html)

Some beginner questions about S/H

I apologize if these have been covered but I could not find them so I am posting some queries.

1) I have read that it is recommended to make the holes one inch from the bottom of the container. Is this only for a certain size of container? I have noticed that in a 32z soup container when I use the one inch rule, the top of the LECA is pretty dry. If I drill the hole one and 3/4 inches up, the top LECA is moist. Is there any reason not to raise the hole a bit?

2) I assume you do not want the roots in the water. Is this accurate? If so, how do you size the container based on the root mass and then prevent the roots from being in the lower portion. Worded differently, how far above the holes do you and LECA before you start planting?

3) if I am using some very short plants (rehab project) so I went with one wide shallower container. Here I notice that the change in the relationship between depth and surface area, it was drying out faster. Any guidance on the shape of the container vs the height of the res?

4) since it is semi hydro I assume that you want the res always topped off? Is this accurate? The ones I have outside are at about half full at the end of the day so I have been filling them up. The indoor ones dry at different rates but I am still keeping them all at full res. Is this proper vest practice or should I let it get more dry?

Quote:

Originally Posted by DirtyCoconuts (Post 909813)

Nope.
The height of the so-called "dry line" is determined by the ability of the LECA to wick (a fixed entity for your brand) and the evaporation rate, which is controlled by temperature, humidity, air movement and light level. Reducing the distance from reservoir to top is certainly one way to affect that.

Quote:

2) I assume you do not want the roots in the water. Is this accurate? If so, how do you size the container based on the root mass and then prevent the roots from being in the lower portion. Worded differently, how far above the holes do you and LECA before you start planting?

That's not all that important. 1/4"-1/2" is fine

Quote:

3) if I am using some very short plants (rehab project) so I went with one wide shallower container. Here I notice that the change in the relationship between depth and surface area, it was drying out faster. Any guidance on the shape of the container vs the height of the res?

Again, it's not the depth of the reservoir as much as it is the reservoir-to-top distance. A bigger reservoir may mean more time until its empty, but as the water is lost, that r-to-t distance increases.

Quote:

4) since it is semi hydro I assume that you want the res always topped off? Is this accurate? The ones I have outside are at about half full at the end of the day so I have been filling them up. The indoor ones dry at different rates but I am still keeping them all at full res. Is this proper vest practice or should I let it get more dry?

No, you should actually never just top the reservoirs up. Remember that fertilizer and plant wastes are in that water. As it evaporates at the top, they remain as residues in the reservoir and throughout the LECA. Merely topping up the reservoir concentrates them, but if you flood the pot every time you water, you 1) flush the medium, 2) saturate the medium, 3) aerate the pot, and 4) refresh the chemistry of the reservoir - all in one step.

Thank you for taking the time, Ray.

If I understand you correctly on the last question, I should then do a full flush and fill on my outdoor plants everyday if they are drying out that fast.

On the flip side...I have two plants in my bathroom and they are drying out very slowly, more like three-four days before I see any noticeable reduction in the res. Is there a rule of thumb for how long you should go between flush and fills if the water does not demand it first?

One way I have found to decrease the dry line on taller S/H containers is to put all the big Leca balls at the bottom and the small ones at the top. The small balls have more wicking power when they are grouped together (more surface to surface contact I think)

Quote:

Originally Posted by Clawhammer (Post 909820)

That’s very interesting....I sorted all the hydroton into > and < 1/2”.....I removed all the “less than” sized bits to allow for more uniformity and to creat bigger air spaces in the container to maximize the aeration. It is quite obvious that increasing the air space and decreasing the contact points would also decrease the wicking ability.

I think I will just keep operating with the deep res for now and the first change( if I am not satisfied with this permutation) will be to reintroduce the smaller LECA back

Quote:

Originally Posted by DirtyCoconuts (Post 909817)

Don't worry about it too much, but keep in mind there is no problem with "too frequent" watering of an established plant.

As to the trapping of moisture, I like THIS TRICK, taught to me by a grower in Scandinavia.

Quote:

Originally Posted by Ray (Post 909829)

that is so damn simple! the most brilliant ideas often are...

wont work for the jewel orchids because there are two or three stalks but this is a great plan for the other few and the outdoor ones for sure

Quote:

Originally Posted by DirtyCoconuts (Post 909842)

Make the center hole irregular in shape so it fits around the multiple growths.

Quote:

Originally Posted by DirtyCoconuts (Post 909813)

I never go under a 2" reservoir these days, regardless of pot size. Many are at 3" plus, and a few have a four or five inch reservoir (big pot). Once you experiment awhile, you'll find how deep a reservoir you need based on your own particular environment.

Regardless, when transferring over to SH you're gonna lose some roots, especially the longer, older ones. I fill up level of LECA to right above hole, and smoosh the roots down into the pot (one doesn't care if they bend around some, as long as you're not breaking them. After transferred and established, if roots grow into the reservoir, no worries. If you upsize the pot, the roots that were already growing into the reservoir are okay to still be that far down.

The more surface area, the faster the rate of evaporation. I only do a wide shallow container for ones that really "crawl" quickly across the pot surface. Otherwise, it's not worth it (for me).

I respectfully disagree with Ray on this one. I definitely don't flush each and every time. I flush once a week. If I notice the reservoir is down during the week, I top up just far enough that water runs out the holes, but don't fill the pot to the top (plain water, no fertilizer, etc). I check them about every 3-4 days in winter (all are inside, less humidity) and every couple of days in summer (much higher humidity, but more rapid evaporation due to higher temps). I'm using RO water, and I don't worry about residual buildup over a week's time. It doesn't hurt the plant to flush each time, but I think it's a waste of resources to flush more often. And if you have reservoirs that are halfway down by end of day, that's a lot of evaporation...especially in a humid environment. Where's the dry line on those that are evaporating that quickly?

And not that ya asked, but I also don't drill two holes anymore, especially when I'm drilling glass. The two holes close together is a great idea when you're on an automated system and not around to monitor a clogged drainage hole for the reservoir. I water everything manually, and can see if water doesn't start pouring out the drain hole. I take a chopstick and stick it through the hole a time or two, and then it drains. You might want that in your bag of tricks when you get around to drilling glass and not having to drill twice.

Thank you!

Great information!!