hosepipe, watering can or underwatering?

[agavemad]

What is your preferred method of watering?
I initially used to water with the hose pipe but found that water sat on the crown of the agaves for too long, also this method I found unreliable as some plants were 'wet' and some still dry, also the wood staging was wet.
I now lift all the plants and put them in a watering tray for a few mins and then swap them over. This is ok for smaller plants but as some of my agaves are growing they are going to become challenging. It also takes a good while.
I have considered the watering can for spot watering but my concerns are when they are dry the water will run straight through and leave the staging wet. With the erratic weather we are having I don't like too much moisture in the green house.
I noticed on a browse of the greenhouses on the forum many members use gravel in the trays, under the pots. Does this increase humidity in the greenhouse in summer? how do you get rid of any excess water from the gravel trays?
thanks Tracey

[matchat]

Hi Tracey,

An obvious point to make is that all plants are rained on from above in habitat. In previous years I used a hosepipe with no ill effects.

Currently I have mixed system. Some plants are sat in trays and watered from below, others are sat on the staging and watered from above and then allowed to drain.

If you use trays it is a very good idea to use capillary matting so that water is distributed evenly. It is trial and error to get the amount of water right. I tried to gauge how much water I used to water each plant in the tray from above and then used the same amount of water to fill the tray. After a few waterings I was able to adjust the amount to make sure plants didn't sit in water for too long.

I don't think that there is anything wrong with water draining away onto the staging and then greenhouse floor. The water will usually dry fairly quickly and if your staging is timber it shouldn't rot if it has been treated with a preservative. The extra humidity can also help to deter red spider mite. If you keep a fan running to circulate the air it will keep your plants happy.

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[matchat]

As for removing excess water from trays; if you use capillary matting you will no doubt have offcuts from when you cut the matting to fit your trays. These offcuts can be weighed down in the tray and hung over the trays edge to draw water out of the tray.

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[graham]

Personally I prefer to always water from above and allow the water to drain away. The only exceptions are the occasions when I feel the soil needs a good soak - if there is a problem with non water-retentive mixes it is that the water does tend to run through quite rapidly when the soil is very dry and in that case letting the pots stand in shallow water for a few hours will allow the soil to properly re-hydrate. I rather like using a solid tray - a gravel tray - and drill a hole at one end as a drain but of a suitable size that it can be readily plugged if I do want to stand the pots in water; of course this does need a relatively level bench preferably with a small gradient to ensure the water does get to the drain. I don't put any material on the base of the trays; I don't feel it's necessary and if there were anything there it's just another place for algae etc. to grow and generally increase the number things to clean - it's very easy to simply put the trays under a tap and brush them clean - with a rinse of hypochlorite or hydrogen peroxide if that's your thing.

I currently have sufficiently few plants that I can use a pressure sprayer most of the time; this gives a decent pressure - for cleaning - and sufficient volume/second to get the job done fairly quickly although if numbers increase, as they seem to be doing, I will have to look at some other method. But I find that the smallish spray at the end of the lance means you can direct the flow to clean the plant or just cover the soil if required. Of course grouping the plants into areas that require the same treatment speeds up the process somewhat but there are times of the year when it does pay to be careful because despite one's best efforts some plants always start earlier, or later, than they are supposed to; in such cases I find that just watering the growing plants is fairly easy - one can be quite precise with these sprays - and does not cause any problems to the still dormant ones because the water just drains through and runs under the other pots, and while they must take up some water as it flows under them, that does not appear to cause any problems (indeed it may just give them a hint).

In my case I don't have a solid floor, just weed-suppressant fabric over the natural soil which does mean that water drains through quickly but in general it's probably more humid than most would prefer but so far I've not had any real problems with that.

graham

[Peter]

It's easy to be too pernickity about watering. I've grown agaves and cacti for very many years and have always watered/fed using a hose fitted either with a spraygun or a hose-end feeder, with the plants on solid, marine ply staging. I don't think that I've ever lost an agave; they seem to relish a good soaking.

[IainS]

Hi Tracey: I also love agaves. I water from above with a watering can - and if I get worried about too much water sitting within the plant, I just blow it out (taking care not to get a face-full of spikes).

With a very few plants, such as those with a fine white powdering on their leaves like Echeveria cante, I still water from above but don't get the leaves wet. Very occasionally, I use a saucer to soak water upwards - but always removing any excess water within 20 minutes.

[DaveW]

A lot depends if you are a "shower" or "grower", I'm speaking of plants now! Those who used to be intent on showing used to avoid watering over the top for cacti since it tended to wash away a lot of the loose wool, just as rain and wind would in habitat, because they liked that "fluffy" look. I remember a visit to long deceased Horace Kennewell's collection in the 1960's when somebody saw all the loose fluff on top of one of his Mammillaria's and with one breath and a good blow removed 90% of it. Horace nearly went ballistic as he had avoided watering over the top to allow all the lose fluff to build up for showing. Just shows how judges in those days rewarded such completely unnatural growing methods.

I still water over the top, but usually with a watering can filled from the rainwater butt. I used to use a hosepipe but our tap water is on the distinctly alkaline side. If it were soft I would certainly prefer the ease and speed of hosepipe watering having a spray on the end of the hose. For one thing mealy bugs hate it, plus it washes the stomata or breathing pores of the plant clean, just as rain in habitat does. Always watering a plant from the base is the equivalent of just washing your feet and never your body to remove all dead skin flakes and dust that settles on it, particularly in greenhouses when there are not even the strong the winds plants get in the open air to blow it off either.

[IainS]

"Always watering a plant from the base is the equivalent of just washing your feet and never your body to remove all dead skin flakes and dust that settles on it....."

Superbly put, Dave!

We have a small Mammillaria guelzowiana and that does get a mixture of being alternatively watered from above and below because of its fluffiness!

[Phil_SK]

2 gallon watering can with a rose, overhead, usually. I have some moderately fluffy Parodia who hold onto their fluff reasonably well this way.

[spinesandrosettes]

First, the answer to your question, for me...is underwatering, in most cases.
I have a large collection of agave, and am somewhat fussy about how I water. Many of my plants are variegated, not run of the mill plants, not cheap either, and so it affects my enjoyment of the plants adversely when I see imperfections which could have otherwise been avoided, through different but perhaps more bothersome watering techniques.
The easy way, and the fastest way, is to just water with a hose from above, perhaps making some effort to keep water off the rosette.
First, one has to consider the quality of the water. The water I use will leave whitish spots on the leaves after repeated overhead watering that won't rub off either. It doesn't adversely affect the growth or health of the plant, but it certainly does affect the appearance of the plant if watered from above. That's not acceptable for me. Do I own a plant just to have it, or because it pleases me to view it? If the former, then it wouldn't matter. But, the true answer is that I derive enjoyment from viewing the plant, and ugly spots on the leaves that remain until the leaves grow out diminishes my enjoyment. By the way, many agave species' leaves take a year to grow out... So, that's a year of looking at something that displeases me.
As a result, I take every single plant, place it in a 5 gallon bucket of water to the level of the soil line, and let it soak. I have a couple of bricks handy to place in the bucket to quickly adjust for the size of the pot. A tiny plant, then a few bricks stacked on top of each other; a large plant, maybe no bricks at all. I then let the water drain out, and put the plant back where it was until the next time. Where exactly that particular plant was situated (which varies according to the plant), regarding the quality, intensity, and duration of the light, is a whole other issue, achieved through trial and error, and I won't even get into that at this time. Anyway, I have found this watering method to be highly effective as far as evenly soaking the entire soil. Depending on how long the plant has been in it's pot, soil (depending on your mix) can compact such that overheard watering doesn't even touch many areas in the pot. It finds the path of least resistance, and drains down through the pot, wetting only areas where the water is prone to travel through. I can attest to the fact that with some medium sized plants placed in the water bucket, and coming back ten minutes later, I can still see air bubbles escaping from the soil. So, do I believe that watering from above the soil is anywhere as effective as watering the way I do? No way, no how, not even close. Taking a few moments to water on top of the soil is quite simply, not as effective as soaking the soil. It might be good enough to get the job done, but is good enough, good enough? It depends on who is answering the question, and the desired result.
Also, water that sits in a rosette doesn't do any good for the plant. One can argue that in nature, rain falls on the plant, so what's the big deal? In nature, agave don't just grow straight up like we force ours to grow in pots. They often grow askew, and water falling into the rosette easily drains out. We value symmetry, and that type of geometric "perfection", so we make out plants grow the way we want them to, not the way (and where) they are naturally inclined. So, when comparing pot culture to nature, one has to also account for the fact that it's not the same thing at all. You can't compare rain on a plant growing at a 70 degree angle to overhead watering of a plant in a pot growing straight up. Remember as well, that in their natural setting, many of these plants are not growing on flat ground, but on hills and such, which achieves the same effect even if the particular agave species does not naturally tilt.
Once in a while, I will quickly hose off a plant if it accumulates dirt and dust on the leaf surfaces, which reduces the efficiency of photosynthetic operations. I'm not looking to impact the waxy film that is present on the leaves of many species which adds beauty, but just get the surface cleaned off. I'll also make sure to blow the leaves dry so water doesn't just evaporate and leave spots.
Plants that are too large and heavy, I will water with a hose or can, but I take extra care to water under the leaves. Also, I'll come back and water the plant a couple of times to improve the thoroughness of water soaking the entire soil inside the pot.
It all comes down to what is important to the grower. Is it time spent or saved taking care of the plants? Is it the pleasure of owning and viewing the plant? I use the time I spend caring for my plants to also enjoy them, inspect them carefully, and stay on top of any developments before anything becomes a problem. As such, watering is not a huge chore, and I'm multi-tasking as well, so not easily bored.
All that said, it comes down to the importance of the particular plant, to me. Also, in general, I'm quite sure that if I didn't care what they looked like, I would just do whatever is easiest and expeditious. If I get to a point where time becomes more important than enjoyment, I believe I would have to rethink whether I should have the plants at all...