E-mail Ques. Fungal problems with cuttings

Q. Dr Myers: I purchased some clear plastic domes to root some native azaleas from htgsuppy this past spring. I am having trouble with the cuttings getting a fungus and rotting before many of them can root. The clear domes keep the humidity high but many of the leaves and cuttings rot before they root. Can you suggest anything I can do to keep them from rotting before they have time to root?
It sounds like you may have too much humidity. You need to lower the humidity a bit to where the plants won’t wilt but the fungus won’t dominate. Taking the dome off more often should help. The domes you bought should have closable slits on the top that can allow moisture to escape. I keep the dome slits OPEN all the time.
Some things I do that may help: When taking cuttings I have a T5 light with high blue light bulbs within an inch of the top of the plastic dome. I keep the plants light regime 18 hour light on 6 hours off. You need to be able to move the light since even without fungal problems you should take the dome off the plants each day. I use a hand mister and gently mist the plants when I take off the lid. Before putting the dome back on again, I wipe all the moisture off the dome. You want to keep the plants wet, but not have everything else wet so that mold spores can thrive. The first few days after taking the cuttings I put the dome back on after I wipe it down. After 2-4 days I increase the time the dome is off the plants each day by 15 min. or so. For most plant at the end of the first week you should keep the dome off for long periods (hour or more) Once you see well developed roots, you should not put the dome back on. Another way to help keep fungus down is to leave some space between the cuttings/plants. Maybe use everyother row for cuttings. This allows some airflow which will help keep fungal growth down. The space may make it easier to spot and remove infected plants before the fungus spreads to other plants too. Every plant species will propagate differently, I have taken cuttings that have large white roots in a week, and other plants take a month to get enough roots to be called a plant.
Another thing to keep in mind is to try cleaning off the leaves/ stems with mild dish soap the day before you take the cutting to reduce the amount of fungal spores on them. If your mother plant has some fungus on the leaves you can bet there are billions of fungal spores all over the rest of the leaves. (If the mother plant has fungus you should try to increase airflow and get the mother plant fungal free first) You should also wash well/sterilize the tray dome and medium before putting cuttings in. You can use a 10-25% peroxide mix to sterilize the tray and dome. You will always have some fungal spores in the air but if you start with everything as spore free as possible, you may have more success. You could also try different mediums to increase rooting speed and/ or cut back on fungal growth, my favorite cutting medium was Rockwool, but I use the coir based rooting starter plugs from HTGSupply.com now. You can also try to use vermiculite, perlite, dirt and different mixtures of each and a few other mediums to take cuttings. You can sterilize these mediums in a microwave if you put them on high for a few minutes. Use small batches if you put too much medium in your microwave some parts might not get hot enough to kill fungal spores.
Good Growing,
Dr. E.R. Myers


E-mail Ques. Aeroponic set up

Dr. Myers
I first wanted to take a second to say Thank You, for your time and your advice.
I have been working with a small aeroponic system. This system was designed and
engineered by me. My question is the reservoir is 15 gallons in size with a temp. of
68 degrees. the water times are 15min on and 15min off constant. I use organic fert
and super thrive. HOW OFTEN SHOULD I REPLACE ALL CONTENTS OF THE RESERVOIR. I currently keep a precise p.h. 5.8 and e.c. as well as ppm of 800 in vegg. I can maintain this without any changes but currently I start fresh every 14-18 days. Is
this O.K ??

First let me say it is very impressive to build your own system. If what you described is working for you and your plants I see no obvious reason to change your routine. You seem to be on top of the pH but depending on what plants you are growing, it sounds a bit low (too acidic). If you are looking for new things to try to improve growth, try raising the pH into the 6.0+ range. If you notice problems with your plants you can lower the pH. I say this without knowing what plants you are growing, if you are growing plants that prefer acidic conditions, you are fine. Most plants prefer a pH that is between 6.0-7.2. As I am sure you know, raising the pH will also affect nutrient use by the plants, so do it gradually. Maybe you could first try to keep it at 6.0 and see what that does… Another thing you might want to think about is to increase your water temperature into the 70’s if it is not too much of a hassle. Roots tend to prefer warmth and this too may increase your plant growth and yields.

Good Growing,
Dr. E.R. Myers


E-mail Ques. Heat and plant growth

Dr. Myers,
Can you direct me to a link on heat and overall plant health research?
As I stated, I am considering LEDs verses HIDs due to the excessive
heat of HIDs and the impact on my plants. I have seen many conflicting
statements on what is the best temperatures for growing and the impact of over
heating. I grew up in Phoenix and in the summer the temps hit 110 plus, yet
plants (suited for the desert) seem to do well. I assume one reason is the
plants can cool themselves by their roots in the cooler soil - another reason
to be a dirt farmer!

And is there anything specifically related to heat and nutrient

Thanks again for everything!

I am a dirt farmer too.

To answer your question, there are a lot of articles on heat stress and the metabolic reaction (at the cellular or molecular level), but I put a link to a general article below that might help.
I don't know if you read my articles on HTGSupply.com’s web page in 2008, I published about one a month, the link to the one about temperature is also below.
Thanks for your E-mail.
Dr. E.R.Myers

Heat stress article

My article which talks a bit about temp.


Your new grow area

I did these posts because I actually build this grow shelf this summer as a project, and I thought it might help someone that wanted to do something similar.
Things to keep in mind when using a grow shelf… The most important thing to keep in mind is what is below the shelf! Water will eventually run off your shelf and hit what is below. It is not a good idea to put a shelf above electric appliances b/c no matter what you think, you will spill water. Also, think about water spilling on the shelf, you could put down a tarp or some kind of water proof material but these tend to lead to fungal growth. It might be good to have a surface that you can wipe up, like painted wood (with exteroir paint). Also, You can increase plant growth with reflective surfaces, In this picture you can see this needs to be my next improvement, (Maybe next summer). I kept the same background so you could see how easy it is to turn any shelf into a grow area. I need to add white paint the the shelf and wall or hang Mylar to help increase light reflection.


Installing a grow light above the shelf

Tools needed: tape measure, pencil, drill and hooks.


Most likely you want the light to hang over the middle of the shelf. You want it to hang centered directly above the shelf. To do this measure equal distance from the back wall to where you will put the hooks. For example, I measured 7“ from the back wall for each hook. This put the roughly 9" wide light in the middle of my 12" shelf. To figure this out for yourself, put the light on the shelf (or shelf supports if you put the shelf up last) and mark where it is centered. (You should not have bulbs in the light when you do this)
The T5HO I got from HTGSupply.com has a total length of 48” and the wires used to support the light (which happily and securely are already attached to the light) are 42” apart. So, I put two marks on the ceiling 7” off the back wall and 42” apart above the shelf. (It might be easier to put the hooks in before you actually attach the shelf to the shelf supports so that you can work directly under where you put the hooks) Keep in mind that you need to leave 3” of space beyond the hooks for a light like this. You don’t want the hooks in the ceiling right next to a wall resulting in the light being propped up against the wall.

Good Growing,
DR. E. R. Myers


Installing the grow shelf

Tools needed: tape measure, pencil, drill, screws, level and a shelf.

If you have a shelf you are going to use you can skip this post. If you are installing the shelf you will need to go out and buy one. The shelf should be a bit longer than the light you will use, and wide enough to fit the trays/ cutting dome. Or, like me you can reuse materials you have. I reused an old desk top for my shelf. When picking out a shelf or material to build one; be mindful that water can be very heavy if you have enough of it!
The shelf needs to be at least 11" wide to support a standard grow tray. An even one foot shelf should suffice to give you a bit of extra room as a bonus. Trays are 21.5" long so you need to have a shelf that is about 44" long.
I have dry wall, you may need to alter some things if you have plaster or a different wall type. When you screw in the shelf supports, try to put the support screws into a stud. Studs (2x4’s in the wall) are supposed to be 16” apart, so you could measure 16” in from a corner, or use a stud finder. You will know if a screw is in a stud b/c it will pull inwards the entire time you drill. If you miss a stud, the screw will spin and not pull in (and you probably can pull it out with your fingers).
You want the shelf to be level -- You could measure down the same distance from the ceiling for both shelf supports (or all if more than two) to get them to line up. This is a good way to get the shelf close to level but, it is best to use a level, so that you know the shelf will be flat. After you hang the first support, put a board across it while you hold in place the next support you are going to hang. Put a level on the board and adjust the second support so that the shelf is level and then mark and screw the second shelf support into place. You could make your shelf have a “slight” tilt. This will ensure the direction that water will flow. If you have too much tilt, you may have problems keeping all the plants in the tray at the same moisture level.
Notice I have a heat mat. A heat mat, will increase your cloning success. Please take a moment or two to read my articles on cloning. (clone article)
Good Growing,

Dr. E.R. Myers


The grow shelf set up

This month I will show how I set up a new grow area. I will use this space for starting clones of lavender and oregano this year, but most any plant could be started here. This type of set up could also be used to start all seedlings or even as a complete grow area for smaller plants like strawberries or African violets. I will try to point out some things that will help you set up a grow shelf. Any comments or suggests would be appreciated, you can send them to Askthedoc@htgsupply.com
Please see my articles on cloning as you read the next few posts (Clone article)
or look over May -June 2009 for more info and pictures about cloning (Clone post)

Good Growing,
Dr. E. R. Myers