I think it was me that posted that, Meg - on the question about dahlias?. Warm, wet, and lack of air movement are ideal conditions for fungal infection on plants. (dahlia blossoms are very susceptible to fungal attack for some reason - even while the foliage seems to hold up fairly well) You're right, not much we can do about the rain. Actually, we can't do much about the temperature either, and I don't know about yours, but my containers are packed tight with pretty stuff, which about guarantees air circulation is a problem. So - the one thing I can do something about is how often the foliage gets wet. ;o)

If I apply fertilizer solution, I use a water can with a long spout & a special fitting I made so I can wet the soil without getting leaves wet. If I water from the hose, I use a high pressure nozzle (the one you use to blast stuff off your drive or siding) but keep the water volume very low so it comes out in a stream too weak to blast soil out of the pot. I can control where the water goes very well with these tools.

There were some things that I wanted to grow that always turned ratty on me by mid summer - maybe Aug 1. Begonias & verbena come to mind right off. When I learned that watering my bonsai from above & wetting the foliage produced all kinds of interesting, but ugly, spots & lesions on the leaves, I applied what I saw to my garden container plants & stopped getting the foliage wet. I also use an anti-fungal spray on containers several times each summer, which also helps.

While a group toured my gardens last Aug, there were many questions on how the containers could look so good at that time of year. I attributed it to happy plants in a healthy soil and foliage that was still almost completely free of fungal problems.

If you grow impatiens & water from above, it's almost certain (at least in MI) that you will be blessed with bacterial leaf spot. The later in the day you water, the quicker it appears. So, if you water from above, try to do it early in the day so foliage has a chance to dry quickly & remain dry, at least until dew forms.

That's my take on it. ;o)

Al ... on his way out to water.

Al,

Does this mean that foliar applications of teas and emulsions are a bad idea? For that matter, I guess I should ask if they really work...

~james

From what I've observed of plants during the couple of years that I used foliar feeding is different plants respond to varying degrees to the help. As far as the teas go, I haven't tried them, but suspect that like foliar feeding, applying the mix at the roots would yield better results, but again - it probably depends on the plant. Some teas, like chamomile, have antifungal properties & the ones currently popular that contain molasses, also take advantage of the anti-fungal properties of molasses.
In short, I don't think there is anything terribly wrong with wetting foliage occasionally, but for me, I now avoid it on all my plants. With more than 125 containers that need water daily, you can imagine that it takes longer to accomplish the chore, but I'm convinced that it's worth it.

I think there are many thresholds in growing plants, and they vary from plant to plant. For instance: How much can you prune off a plant before it dies? For some, you can prune it off at the roots & it will come back. Other plants may only tolerate a 25% reduction or less. How long can a plant stay wet before roots rot? For willows - forever, for portulaca, maybe a couple of days, depending on the soil & temperature. There are lots of variables, too. The plants I mentioned above, begonia, verbena, impatiens, just would not tolerate top watering for me, and my containers always petered out by Aug. Now, it's frost that ends my container season.

When I top-watered, I'm sure that I had watering almost all my plants after work working against me (because the foliage often stayed wet all night long, well into AM). Somewhere there is a threshold as to how much wet foliage a plant will tolerate before fungal infections occur. Humidity, air flow, temperature and amounts of sun received will factor into the equation, too. E.g. readers that live in more arid areas will be less concerned, but in areas where humidity is often over 50% for extended periods, it's probably worth considering. I just figure it makes no sense to tempt fate. When I think of how hard I work at planting & getting my containers looking just right, it kind of makes me want to go the extra mile to keep them that way.

Some may doubt or have questions, but I am certain that the tremendous improvement in foliage appearance of my containers (especially late season, when many are discarding their container plantings) is due to the change in watering technique & healthy soil.

Al

I too wonder about the 'rain' issue. However, I now water my plants only at soil level unless I am doing a foliage feeding, then I do it only in the morning (so it has to be on my day off).

I don't know what the difference is but my plants are much healthier.

Ok, I understand better now. Thanks, Al :-)

And I'm going to try hose watering on the 'jet' with very low pressure. Will probably take a lot longer, but it makes a lot of sense to me now.

I've followed instructions on not getting the foliage wet, and it really seems to be helping. But some of my leaves still seem to be having a problem. What kind of anti-fungal spray do you use and how do you use it? I've searched some of the gardening supply sites and can't seem to find any. Thank you!

Connie - I use several fungicides, depending on plant, problem, season or conditions, but I'm somewhat reluctant to suggest their wholesale use for every fungal problem. I've also found that fungicides are most effective as a preventative, rather than a fixative. It's a chore, but remove the affected leaves & if plants appear too far gone, remove the entire plant. Do not compost the affected plant parts. Burn if you can, or put in a plastic bag & dispose of in trash.

Make notes for next year about what plants were fungus magnets & eliminate them from your containers, or start anti-fungal applications before they are apparent. I save all the plant tags from the plants I put in each year. At summer's end, I write the botanical & common name of the plant, along with observations of its habit and/or problems. It really helps me eliminate making the same mistake three times (everything performing poorly gets a second chance in case it was a cultural issue I can correct or a disease issue I had no control over).

You can try any/some of the suggestions in the link I provided, or if you wish to use a chemical fungicide, contact me off forum & I'll offer a suggestion.

Al

Here is a link that might be useful: Some organic solutions

While I generally pay attention to whatever Al has to say, I've also learned that sometimes plants just DO NOT like whatever you've done, or not done, to them. For instance, speaking of dahlias, I bought a lovely little dahlia plant back in April and potted it up. It did great. Then, I bought two more of different varieties, potted them up, and they both wilted and died forwith. Go figure. The first one is still going great guns. The other two have long been replaced with other plants.

You can make yourself crazy trying to figure it all out.

On days when I'm off from work I like to water in the morning - before the sun starts beating down on everything. I'll walk around from pot to pot. As a finishing touch I'll usually spray the foliage - just to clean stuff off. It also provides drinking spots for the bees, wasps, etc.
On work days, when I water after I get home - I only water the soil & keep the leaves dry overnight.

I seem to recall reading somewhere that getting the leaves wet is only a problem if it is a bright and sunny day. Something about the water drops focusing the sunlight, like a magnifying glass, and scalding the leaves. This makes sense to me, and helps explain why rain drops on leaves is not a problem, as skies are not bright and sunny when it rains. - Fred in Maine

There is no magnifying effect. It is physically impossible for water on leaves to focus light so that leaves burn. Any burning of leaf surfaces as a result of water droplets comes from dissolved solutes causing water to move out of plant cells via reverse osmosis. Water on leaves is a problem because it provides an ideal breeding ground for things fungal, which is often more a problem in containers because of the crowding of plants and the lack of air movement that promotes.

Al

Al, you mentioned that your containers are "packed tight"! What is your definition of "packed tight"? Have been concerned that I've over packed some of mine! 99% are annuals. Thank you. Ann

Must get a long snout can.

When I build containers for floral displays, I take each plant & rip off the bottom half of roots. I then work my fingers up into the rootball from the bottom, moving outward & removing much of the soil. This actually sends a chemical signal through the plant which stimulates root activity and allows me to "pack" twice as many plants as the average container grower would put in a container. I really recommend you try this technique - whether you "pack" your plants in or not, and even with plants planted out. Though it seems harsh, it is a good kick-start for freshly planted material.

This "packing" really hampers air circulation at the center of the container - even more than normal, so I have found that regular preventative applications of an anti-fungal spray, along with keeping foliage dry, goes a long way toward eliminating fungal & mildew problems.

One thing to note: I would expect that fungal issues would vary with the humidity (and air flow) in an area (of the country), but once you get a fungus, it's usually there to stay, though they don't always migrate to all the plants in a container.

My opinion: You really can't pack a container too tight. Even if roots become really tight, the primary impact is on plant extension (elongation of stems), not on bloom profusity or foliage quality, and that usually occurs late in the season. You do need to be reasonable about container depth, however. IOW, you wouldn't want to pack 30 petunia plants in a 12 inch container that was 3" deep. With too little soil, water & nutrient holding ability are a big challenge.

Al

Thank you for time and your explaination! Have had occasion where I've removed alot of soil from around roots and now will be less timid about removing lower area of roots. With containers that I feel are overly full, I run my hand through the plants to kind of shake them up and allow more air?! Ann

LOL! I'm another "packer" when it comes to planting containers.
A few times I kept a bucket of waier next to me while potting. When I take a plant out of the cellpack, I swish the roots around in the water. You can get LOTS of plants in that way.
It all depends on:
1. the plants (great for annuals)
2. the pot
3. how much time I have to mess around with extra steps.

LOL!

tapla, everytime I read one of your posts I always have tons of questions pop into my mind! (or I go.....hmmmmm... that makes sense!) :)

First... is it a fungal thing that makes dahlias, african marigolds and the non-stop type begonia's flowers all of a sudden turn to big balls of black mush? I've had this happen before in my flowerbeds but thought it might have been over-watering.

Second... your explanation of what you do with the roots when potting something up made me think. When I bought 8" hanging baskets of supertunias I repotted them into 12" pots and loosened the roots up a little, but not a lot. (As you know, these baskets don't have much soil in them when you buy them). Now I find I cannot give these things enough water and I bet they are just as root-bound now as when I bought them. So I am thinking I should have been "root-brutal" like you when I repotted them...then they would have had more soil (and air) in the pots and wouldn't be constantly thirsty and hungry. Am I right?

"You can make yourself crazy trying to figure it all out."
Barb, your comment made me think of my little 2-yr old granddaughter and how I should try to adopt her philosophy on things. (Sorry, folks, here comes a grandmother's story...) ;)

One day my hubby was mowing the lawn and ran out of gas. Our granddaughter saw him scowling fiercely at the mower and said, "Poppie, what is wrong??" "Oh, I ran out of gas!" answered Poppie. She solemnly looked at the mower then at him, shrugged her little shoulder and said in a wise and consoling voice, "Oh well, Poppie... it happens." Then she quietly walked away leaving him standing there with his mouth hanging open.
(the story loses a lot when you can't "type" voice inflection!) :)

So when it comes to the many mysteries of caring for plants I think I will stand back now, relax, not drive myself crazy and just think... "oh well... it happens." Afterall... we do what we can do, learn what we can learn, and realize that mother nature will always have more control than us. :)

This "wet leaves" issue is always on my mind when considering the benefits of an overhead automatic watering system in a greenhouse. Everyone says it is the way to go... then you read the growing-on directions for many of the plants and see "do not wet the leaves". Then you wonder how you water benches full of flats of potted-up plugs without wetting the leaves?? Then you realize why ebb-n-flow tables are so expensive (and desirable!). Oh, well... you do what you can do....

DaisyLover
First) I think more often than not (wish I could end the sentence right there, but ...) that many awful looking containers are the result of a couple of things added together, but yes, when your plants melt to mush, it's a fungal thing and probably helped along by watering habits. One issue, is root rot from either over-watering and the lack of air in the root zone, especially when it's hot. Even with adequate aeration, over-watering has am impeding effect on a plants ability to absorb water. This is complicated, so I won't go into it unless I'm questioned on the statement. Stressed plants (from root issues) are much more susceptible to any old fungus that decides to take up residence, as well as insects or other pathogens. Add in watering from the top, & you make conditions absolutely inviting for fungal colonization. I know I keep stressing aeration over & over, & you MUST be sick of hearing it, but it is the key that most of those with continual problems with their containers are lacking. Strong roots = strong plants, able to fend off attack more effectively.

Second) There was a torrid discussion last year on the New to Gardening forum after I mentioned that I really mauled the roots of transplants. I was taken to task by several posters for the ridiculousness of the statement. After awhile, some of the more experienced gardeners came to my aid & mentioned that they also treat plants similarly when potting containers or planting out. I think that initially, there is much benefit in removing portions of the roots & causing some injury. Though this isn't a very scientific way of putting it - it alerts the plant that roots have been damaged and growth regulators stimulate rapid root development. After awhile, if your soil is good, the roots will colonize the entire container. This doesn't spell doom for the plant, as long as you are diligent in providing adequate nutrient and water rations. If you can do this, the only adverse effect you're likely to notice is diminishing elongation - the first symptom of tight roots (mentioned up-thread).

Third) Green house environments are very conducive to fungal development. Good ones will always have the floor swept clean & dead/dying plant parts are removed & disposed of. Frequent applications of various fungicides (along with cleanliness) are the weapons of choice to keep the product disease-free, healthy & salable while frequent insecticide applications keep critters numbers at an acceptable level.

It's easy to get frustrated & think you're driving yourself crazy when things don't go as we plan, but keep on trying to learn. It's like being asked to put a puzzle together that's divided into three groups of pieces. You might be given the border pieces first - they're the difficult small pieces, tough to figure out & put together, but once that's under your belt, you get the second group of pieces - they're much larger & easier to figure out. Then, with the first two groups of pieces assembled (your base of knowledge) you can easily figure out the where the big, easy pieces go. These are your day to day plant growing problems that, because you already have 90% of the puzzle under your belt, don't present near the problem the first pieces did.

You probably already have many more pieces than you think you do. I'd bet on it.

Good luck.

Al

"stressing aeration over & over, & you MUST be sick of hearing it"

Nope... I'm not. :) Actually it was funny... I read your long post about soil mixes and thought "Goodness, that makes sense!" Then I happened to be looking at my old Ortho Container Gardening book from the 70's that I have mentioned and I slapped my head and said "DOH!!" There it was... where it had apparently been lurking for almost 30 years... the exact same thing you were saying (although not in such detail) and very similar soil mixes... and in all these years I never noticed it before! Talk about feeling dumb! :) And the year of the mushy plants was a very wet rainy year (and I'm sure my flowerbeds didn't have great areation) so I figured the excess water caused the flowers demise.... I just never took it a step further and realized it was a fungal thing. "Fungal" is a concept hard for us common folks to understand. i.e. 'your plants rotted because of a fungal disease'....'naw, they just rotted cause they got too wet'. :)

"Strong roots = strong plants"

Couldn't agree more. That's why I was so amazed when someone with a commercial-sized greenhouse didn't use the bench heating (that came with their greenhouse)..."because it makes the roots too big..." duh...I thought you wanted a strong healthy root system? :)

"torrid discussion.... after I mentioned that I really mauled the roots of transplants.... I was taken to task for the ridiculousness of the statement"

Am I the only one who remembers the older lady who was on TV years and years ago and she shocked everyone by her brutal handling of plant's roots when repotting? I don't remember her name but she always reminded me of Julia Childs probably because of her slap-dash methods (although I don't remember a glass of wine...) :)

"isn't a very scientific way of putting it - it alerts the plant that roots have been damaged and growth regulators stimulate rapid root development"

I don't know why people find this hard to understand... after all, they do understand that if you don't eat properly your brain sends signals to your body that you need more fuel so it rapidly starts storing stuff up for you to compensate (also meanwhile messing up your metabolism!) Point is... the signal is sent... and the body reacts. (Now how's that for an even less scientific illogical explanation??) When I'm potting up 606's or 3"-4" starter plants I always hack into the root ball and spread it out a little. It just amazes me I didn't do that with my supertunias. another "DOH!"

"Green house environments are very conducive to fungal development..."

Thus the reason good air circulation is so very important in a greenhouse. (sort of like the reason you get that foot thing when you keep hot sweaty feet inside sneakers too long). Probably why I am always always barefoot! So I guess the good air circulation in a GH is to counteract the effects of overhead watering... (along with watering early in the day).

"Frequent applications of various fungicides ... to keep the product disease-free, healthy & salable while frequent insecticide applications keep critters numbers at an acceptable level."

Now this is an area that I want to learn a lot about (along with a few million other things I want to learn!). I never use insecticides... not since I tried it years ago on a house plant and killed it. So now I need to learn as much as I can so I feel comfortable and knowledgable about using fungicides and insecticides. (or organic methods too... before all the organic people jump all over me). I know of one greenhouse that uses the yellow sticky cards like old-fashioned flypaper... not just as a warning system for pests but as a prevenative step. I'm not sure this is the proper thing to do though.

I do know you can have a nice GH with a controlled bug population and then you open a box of plugs and have a kazillion bugs fly out! And this is exactly why I would like to have a second, smaller GH just for like a staging area I guess it's called... a place to open new shipments of plants without risking releasing stuff into your other greenhouse full of plants. And it could also be used for a hospital area, or a work area for assembling stuff. I just think it makes sense to have two. :) (pretty good since I don't even have one yet!)

"You probably already have many more pieces than you think you do. I'd bet on it."

I always did all the edges of my jig-saw puzzles first. I think I'm working on the middle pieces now... but such a long way to go.... so I wouldn't be placing any bets on me just yet. :) I can't even find places around here to get the ingredients for your soil mix! I need to really just stop thinking so much, decide on a starter greenhouse to build, register a name so I can order from the large bags of perlite wholesale supplier and start practicing. And if I can't find bark fines I'm gonna run a bag of mulch thru my chipper/shredder! By the way... perlite comes in fine, medium, and coarse... which do you use? I really am not happy with any of the packaged potting mixes (even Miracle-Gro).

sorry I really got off topic here... this all belongs elsewhere... :) Oh, well....

I read the whole post & only found one question that wasn't rhetorical.

Coarse.

Hope Meg's OK with having her post shanghaied?

;o) Al

Al, thanks for your answer. Not only did you give me the answer to my question, but so much additional information. When I planted my very first container plant (hydrangea) a year ago I had no idea that there would be so much to learn. But I'm enjoying all of it! Thanks again!

I'm glad I seem to be doing most of it right . . . I need to be a bit rougher on my plants when I'm setting them in containers. Al, thanks for all the detailed info here and elsewhere.
To return to the beginning of the thread, rain happens, and plants in open areas make it, some of the others might not. For me, watering wands are the tool of choice, and if I were growing stuff that was particularly subject to fungus, I'd probably get a seedling nozzle (easier to tuck under the leaves). I've not had much fungus problem, however, even with the heat and humidity we have down here. Biggest issue seems to be with some of the artemisias, whether the watering is natural or assisted.

I hear you. Even as careful as I am about wetting foliage (& I even use a fungicide) I still have dahliettas in containers I'll need to remove soon because the foliage is spoiled. They're off my list of acceptable (for me) container plants. ;o)

Al

Don't mind at all having the post shanghai'd! I still have so much to learn, and it always leads to more info.

Can I jump in here and ask some questions to Al?

Al, you seem to be the guy to ask, as you are quiet insistent on not watering from above. I use soaker hoses extensively on my beds, only a few do not have them. This year, we have had a drought here in Missouri, and literally went almost 6 weeks without any rain. I know it is not good for the environment and for farmers, but it has been great for growing flowers! IF, that is, the flower grower has soaker hoses. If not, it has been a summer from hell for gardeners using watering cans or hoses. Almost all of my plants have grown uniformly, couldnt have been any more perfect, and I think all the success has been due to my being able to totally regulate watering and fertilizing. The only time the tops of my plants have gotten wet was when I would fertilize.

And then.............the rain from Hurricane Dennis came.........and it stayed for two weeks streight. And now, I have all kinds of fungal problems.

My question to you is (Al), do you practice any means of "extreme gardening" to keep rain off your flowers? I mean, I know you cannot control what goes into the ground, but some kind of effort to keep flowers from getting spoiled? For example: petunias. I detest what rain does to the flowers. I, personally, prefer the non-waves over the waves (though I love both), and am quite diligent with deadheading. However, all it takes is one rain shower to destroy the flowers, and then it is like starting all over again. Also, impatiens get destroyed by rain.

I know you are going to think I am a complete fruitcake, but next year I am planning to build some kind of "umbrella" for certain areas of my beds. In fact, I already plan on building cages for certain areas to keep rabbits and other animals out at night time--these cages will be exclusively used at night time only. I love my petunias THAT MUCH. What I envision for the rain issue is, when anticipating a rain storm, simply put the cages on top an cover with plastic. Not tightly to seal out air, just to direct the rain off the flowers and foliage.

Am I a complete loonatic here? Or has this been done before and is "old news"? Has anyone else ever considered this or actually done it?!

Al, can you give me some tips for doing this? I'd appreciate you!

Let me reiterate what has been mentioned earlier in this thread with a slightly different perspective. In order for a plant to be infected it needs a virulent pathogen, a susceptible host, and the proper environment. These three components are known as the disease triangle. And they must occur in the proper sequence. For example, if the leaves are wet, but there are no spores, then the leaf won't become infected. Similarly, if the leaves are wet and spores are present, but the temperature is too high or low, then the leaves won't become infected. Watering at night is not good, as has been mentioned. Along with the rain, Hurricane Dennis probably carried spores, which caused leaf infection. What Ellen_inMO desires is called a rain out shelter and I doubt if they are commercially available. A search on Google might provide some papers on this topic. In order to construct such a shelter, one needs time, money, and electrical and mechnical knowledge.
agmet_al

Hi, Ellen. Not watering from above has proven extremely effective at keeping fungal issues under control where I live. For those in more arid climes, it may be a total non-issue. I don't do too much in extreme gardening as far as rain goes. Some of the pines & junipers (and others that like it dry) might get their pots tipped or moved under grow benches during prolonged rainy spells, but that's a root issue. I do use anti-fungals on containers in a preventative program, and, as noted, try hard not to wet foliage more than necessary. I am 5 applications into a Messenger program this year & simultaneously do a foliar feed & Daconil application every two weeks when applying Messenger.

I think what you are considering is admirable, but I can't help but wonder if results will be commensurate with (your) energy outlay. Aside from rain, there is fog & dew to consider. Will the structures shade the plants & possibly impede air flow? If so, how much of the benefit of keeping foliage dry would be offset?

Perhaps you could investigate organic "home remedies" that have anti-fungal properties? Attention to root health, and good watering habits with adequate nutrient supplements will promote a more vigorous plant that can fight off disease more efficiently, too.

I wish I could help more with the conceptual phase of your proposed project, but I'm coming up short of ideas.

Take care.

Al

Al, thanks for giving me things to think about. The fungal issue of course is a concern, but moreso my concern is about keeping my flowers looking nice after the rain. I have many people who come visit my display gardens, and if there is some way to keep it all looking perfect, I want to go to those extremes.

I know, you all think I am insane. But what if it works?

I would only cover the plants if I anticipate a really long rainy spell, or a storm.

agmet, I just now seen your post. My set up that is in mybrain is really simple. Since I will obviously have to cage in certain beds if I intend to have beloved petunias, I am devising a set up where the material I use (most likely will be small squared chicken wire)will be rolled out like a hose reel, then be weighted down with landscape timbers (on the ground), which will easily be slid out of the way during the day (behind the display bed). I will have some stakes insterted to keep the wire from lieing on top of the plants, maybe about 6 inches above the plants, or more if necessary. What I envision is simply laying a tarp of some kind over the top of this, weigh it down, and none of my flowers will get spoiled, and doing this ONLY when it rains. The cage will not get covered at night if there is not rain. In the morning, I will roll up the chicken wire, which will be on a very simplemade hose reel type object, slide the timbers out of the way, and viola! No rabbit damage, and perfect petunia flowers.

As far as caging my plants, I know some will recommend a ton of ways to keep the rabbits out. I have tried everything you can think of, and NOTHING works. Homemade concoctions or expensive sprays will only last a day or so. I lost about 450 annuals that I grew from seed this year to rabbits. I want to take every measure to make sure this doesnt happen again.

I hope explaining that will help others to understand why I want to do this!!

My observations about the rabbits..........why do they stop eating the plants once the plants get full sized???? After about a month after everything was planted, the rabbits stopped feasting, but they are still all over the yard.

I hate rabbits.........

Ellen_inMo: Your idea will work if rain falls at times that are convenient to people. That doesn't happen often, e.g. rain falling at 2:30 in the morning or while you are shopping. Here is a general idea for a rain out shelter. First you need a rain sensor to tell you if it is raining or not. In order for this sensor to work and control opening and closing of a covering system, this sensor must be connected to an electronic device that can measure the sensor and control relays to open and close the covering system depending upon the status of the sensor. The covering system can be similar to the automated awning systems that one sees advertised on television, but placed horizontally at a slight angle so water doesn't pool on the material. As one goes from generality to specific details, one usually encounters problems. I hope this overview is helpful. Regarding rabbits, the following is just a thought. You could try a motion detector in place of a rain sensor and the relays could open and close several devices to make sounds that rabbits don't like or emit odors in a random manner so the rabbits won't catch on to a pattern. No doubt this topic has been and will continue to be discussed on various threads in different forums.
agmet_al