My plants are fruiting,I'm using Miracle Grow for tomatoes. Pots are all 18 inches across. Fertilizing once a week. Thank you for your reply.

I'd wait a day then, although it's hard to overwater a fruiting tomato. As for your watering style, I believe it's the amount of fertilizer you end up providing that matters, so the more fertilizer you put in the water, the less water you need. I still hope someone with more experience than me could confirm this.

So these are tomatoes grown in a container? What kind of potting soil did you use? If a high quality, fast draining mix, there is not a lot of concern about overwatering........it can happen but not that easily achieved :-) But don't let them sit in water-filled saucers for any length of time. That is the equivalent of sitting the pots in a bucket of water. The water (and/or diluted fertilizer) needs to be able to flow freely away from any drainage holes.

btw, skipping a day or two in the fertilizing schedule is NBD!!

Boris, If you have less water it would make a more concentrated solution. I really don't think you want that. First thing I think abt. is burning the roots???? I don't know what I'm talking abt .lol

gardengal48 (PNW Z8/9) I think you hit the nail on the head Ive been watering the hell out of them . Every time the saucer is empty I refill. How abt soaking the plant with water or fertilizer is that ok ? So are saucers necessary for outside use? I see where they play a role indoors .PS It was my understanding that filling the saucer was a way of watering thru capillary action so watering from below would prevent you from over watering.

Water when the plants and the soil tell you.....not when the saucer is empty (it should always be empty!!!). You want to water thoroughly when you do so that water runs freely out of the drainage holes (and is not collected by any saucer). If you water thoroughly you do not need to soak the plant or plunge it into a bucket of water or dilute fertilizer although that could be a perfectly acceptable method if a small enough container. Mine are grown in 20G pots and are currently about 6' tall so not anything slightly portable :-))

No saucers for any containerized plants. If you do use them (to protect wooden surfaces, etc.), dump out any water that accumulates immediately.

ETA: Allowing water to remain in the saucer will just serve to raise the perched water table, that portion of the soil in the bottom of the container that never completely dries out. The higher that is allowed to get the greater the risk of overwatering and root rots. And when you water you want to do so from the top down (container soil surface), not from the bottom up :-))

So when does capillary action come into play. Why is my soil moist about 2 inches from the top . My saucers are about 2 inches high, the rim of my pot 20 inches. Please don't get the idea that I'm criticizing you I'm not . I will follow your directions. You know a lot more about gardening than I'll ever know. I'm just trying to learn. Are the exclamation points necessary? Thank you

"It was my understanding that filling the saucer was a way of watering thru capillary action so watering from below would prevent you from over watering."

"Capillary action" if you mean water wicking up from the saucer into the soil in the pot isn't really applicable unless you are using a self-watering container that is specifically designed to wick water up from the built in water well.

Plants grown in normal non-wicking containers will only wick water up to a certain level, what is referred to as a perched water level. What level that is all depends on the size and shape of the container andth e mix it is filled with as gardengal said. But in general it is approx. 1/4 -1/3 of the way up. That may be enough for some of the roots in an older larger plant but you can't count on it and you risk root rot and suffocation. So water is added slowly from the top down until it begins to appear in the saucer below. Then stop.

If the saucer continues to fill and over flow the saucer it was too much and you need to drain most of it out of the saucer. Same for when feeding. Takes practice to discover just how much and how fast to apply without waste. It doesn't hurt for it to sit in some liquid for a brief period of time but not for long. The primary purpose of the saucer is to protect whatever the plant is sitting on like the deck rather than protecting the plant itself. ;-)

The crucial soil level for water is the 6" down area +/- an inch. That is where most of the roots are. So if your soil is wet 2" down then watering isn't needed at that time.

Dave

Very informative Dave thank you

usually you always want the plate empty. after a good rain fall it's good practice to go around emptying them a bit by tilting the pot to the side.
some of my pots i drilled a drain hole because they don't really serve a purpose except for things mentioned earlier about pots on a deck or a surface you do not want to get wet.

A simple way to think of it is that if capillary action were that effective in soil, we'd never have to water at all, because capillary action from the water table down below would keep the soil moistened. The water height achieved in capillary action is highest in soil with the smallest micro pores between grains. Fine sand, for example. Roots are able to bring water up from depth only if they are very thin, or the tubes that make up the roots are very thin.

William, if I may, some confusion can enter because - if done properly - it is perfectly fine to 'bottom water' trays of germinating seeds. This is done while the seedlings are just establishing, and bottom watering - employing capillary action - is a good way to keep small pots and trays of soil moist. One should learn how to manage 'damping off' problems, but with a little practice and experience, watering from trays works just fine for the first stages of growth.

I don't grow in pots or containers but to my way of thinking and understanding that plants feed from their root tips and their roots will be at the bottom of any container - to me it makes sense to water from the bottom. That would also not wash the nutrients out the bottom as you would when watering from the top.

Even outside I would want a drain pan under the pot when possible. But as I said I don't grow in containers.

I know the last two posts were trying to be helpful but I think they may just be adding to the confusion :-)

First, seed starting is not at all the same as growing a plant to maturity and fruition in a container and different principals apply.

And typically, successful container culture requires a pot with plenty of room for future root development - if you have a containerized plant with roots that reach fully to the bottom of the pot, it is time to up size the container or root prune. Neither of these is the slightest bit practical when growing tomatoes! So watering from the bottom up may not provide anywhere near the watering requirements the plants need, particularly if the roots have not developed to the point where they can access the PWT. And fully flushing the container with water helps to reduce fertilizer salts build up which can be a concern with any containerized plant requiring routine fertilization. You also will not get full benefit of any fertilization if you only water from the bottom up........most of the fine feeder roots of any plant are located just below the soil surface.

Ideally, you want any containerized plant to be elevated slightly above a solid surface so that immediately negates using a saucer or drain pan. Free and fast drainage is a requirement for pretty much any containerized plant (except bog plants.....which tomatoes are NOT). Anything that impedes or prevents that fast drainage - like direct contact with a concrete patio or wooden deck, etc. can be problematic. That's why many containers are sold with a bottom lip or protrusions that actually lift the container slightly above full direct contact. Using pot feet or bricks, etc. to elevate will help also. A container resting on the soil is less of an issue as the soil acts like a wick, drawing excess water out of the pot, unless the ground soil itself has drainage issues or is saturated.

Container gardening is NOT the same as inground gardening and you cannot successfully apply the same principals and get the same results. There is a very thoroughly researched science involved in container gardening. You might find it helpful to spend some time on the Container Gardening forum and read up on some very informative postings on container soils and water movement and fertilizing containerized plants.

Yes, the reason I personally was trying to be helpful was that the cautions about bottom warning of containers above lacked explanation of 'bottom watering' as a common, efficient, and perfectly acceptable practice at certain stages of growth. Unfortunately, and I know it wasn't purposeful, it sounded like a thorough condemnation. Sometimes the written form of communication in such matters leaves a little to be desired.

I understand that the OP is not discussing early growth of seedlings, but an inexperienced gardener may not understand next year when people begin championing bottom watering of their seedlings.

I know that you too were trying to be helpful, but how about we take a step back and give an overview. I'm not going to detail PWT (Perched Water Tables,) as its been done before and others can explain it better than I, but if no one minds, I'll try to simplify it as follows...

At certain times, bottom watering is a perfectly acceptable, and yes, beneficial practice for plants in containers. For such plants as tomatoes, that time is in the germination and early seedling stages. Later, as the above comments discuss, keeping a maturing, or mature container plant in a saucer can become detrimental. As Dave mentions, there are instances of reservoir feeding that rely on bottom watering and capillary action for such mature container plants, but those are specific examples where proper planning and design are applied.

To get more detail, and/or if a person is interested in learning more, I fully support gardengal's recommendation of checking out the Container Gardening, as well as the Growing from Seed forums. :-)

So would bottom watering be useful for suboptimal growing conditions, like my 5 gallon grow bags where the roots do reach all the way to the bottom? I ask because I tried it on warm dry days and the 2+ gallons that fit in the saucer are mostly gone in several hours. Before you ask, my containers are elevated, so are not touching the bottoms of the saucers.

Boris, does it mean that your bag is in the saucer but is not touching the bottom.How does the bag get the water ? I'm trying the air pruning this year cant wait to see the root system. My plants are doing very well,sounds yours are too.

The bag is not touching the bottom of the saucer, but it is below the water line if I fill it to capacity

I really don't see how container bottom-watering can be beneficial at any stages. At later stages, the roots will be immersed in water. If you want to do hydroponics, just do that. For germinating seeds, if you want to keep the soil moist without watering, just cover the mix with plastic. Remove when the seedlings emerge. To the extent the PWT is higher than the soil surface, evaporation is just going to leave a crust of salts and perhaps fertilizer on top. Those salts and fertilizer get wicked up with the water. That can't be healthy. Ever make a salt "crystal garden"? That's what's happening here. In fact, the concentration of salts and fertilizer in the moist soil will increase with time in the topmost layer.

I can see how collecting the water that percolates through containers, and applying that from the top as irrigation liquid can be smart. You conserve and reuse fertilizer that way. But again, evaporation is going to concentrate things. Keeping the liquid volume constant by adding water would help.

@William Cohen IMO growing tomatoes in containers is very difficult. If you have no other choice - so be it.

If you end up with Blossom End Rot (BER) please note it is from inconsistent watering and not from the amount of fertilizer you are using. Just remove any affected fruit and change how you were watering. Try something diff.

For the thought that tomato roots will only reach the bottom if/when the container is too small? I can't even imagine what enormous container would be needed for the roots not to reach bottom.

If you can grow tomatoes and other plants in hydroponics how/why would watering from the bottom cause any problem? Esp. root rot?

Tomatoes need consistent moisture esp. when fruiting. IMO that is diff. (where I am at least) in containers as the wind dries them out quickly. I did try it one year in 5 gal buckets and I did water from the top.

If you have a choice next year you may want to plant the in the ground if that is possible.

"If you can grow tomatoes and other plants in hydroponics how/why would
watering from the bottom cause any problem? Esp. root rot?"

Properly done hydroponics takes trouble with maintaining a reasonably sterile system. With an anti-microbial, anti-bacterial solution. Totally different than gardening with soil. Yep, if you used "dirty" hydroponic liquid, you'd probably get root rot. Ever wonder why hydroponics is done with synthetic or synthetically based nutrients rather than, urk, compost tea?

No.

"IMO growing tomatoes in containers is very difficult."

No more difficult than growing anything else in a container :-) In fact, growing 'maters in containers is probably the most desired method in my area. It is difficult to generate enough heat here in summer to encourage ripening and growing tomatoes in black plastic nursery pots (yes, big ones - 20G) allows the soil to heat up sufficiently and the plants be moved to provide maximum sunlight and any available reflected heat.

FWIW, I have never grown a tomato in the ground - I have only used containers - and I realize a healthy crop each season, usually more than I can consume myself so I share with family and friends. No diseases and no BER.

"IMO growing tomatoes in containers is very difficult."

I should have explained the year I grew some plants from seed I put 2 in 5 gal buckets, 2 in the ground, and 1 in another bucket to grow upside down.

As I said the constant wind (breeze) wicks away moisture. That is when I decided IF I can plant in the ground that I would. Esp. if/when going away during the growing season. No one cares for your plants/pets/etc. like you do. YMMV

{FWIW, I have never grown a tomato in the ground - I have only used containers -}

If that is all you know how could you possibly compare to growing "in the ground"?

Because it doesn't make a whit of difference what sort of plants you are growing - container culture is just very different from inground growing. Period.

And I do grow plenty of other plants in the ground. btw, I do this professionally. I am a consulting horticulturist and visit others' gardens on a daily basis to give advice, diagnose problems and make suggestions. I am not just a hobby gardener.

{Because it doesn't make a whit of
difference what sort of plants you are growing - container culture is
just very different from inground growing. Period.

And I do grow plenty of other plants in the ground. btw, I do this
professionally. I am a consulting horticulturist and visit others'
gardens on a daily basis to give advice, diagnose problems and make
suggestions. I am not just a hobby gardener.}

That doesn't explain how you could possibly compare.

{........most of the fine feeder roots of any plant are located just below the soil surface.}

So in the ground roots feed from a different location?

namaste

Sorry but your point....if there is one......makes no sense. I grow plants in the ground and in containers and the differences exist regardless of the plant. Container culture of ANY plant is distinctly different from growing that same plant in the ground - it's the methodology, not the plant, that makes the difference. And while I may not grow them personally in the ground, I am very familiar with growing tomatoes in the ground as well as in containers. Yes, I can make comparisons!!

<Yes, I can make comparisons!!>

Which is easier?

Which is more stable/reliable?

Which is less finicky?

I prefer in the ground when given a choice is all I was trying to say. But that is for me, for the reasons stated; not for others.

FWIW, there are a host of pests and diseases that attack tomatoes in the ground that affect container plants less often. I'd have to say that, in the "stability and reliability" column, container gardening probably wins. More likely I can reproduce performance of a previous year with a container, than in the ground. I have a lot more control of my soil in a container than I do the soil in the ground.

That being said, I prefer the ground too, but mainly because I have good soil and a long growing season. For me, the ground is easier, for others, it may not be.

gumby, your intentions are good, but your way of thinking is wrong..

the reason plants can live in hydroponic with roots in the water, yet die in a container with submerged roots is that they are raised differently. like all other life on earth.. things adapt to that growing environment.
plants in hydroponic form different roots than plants in soil. the roots towards the bottom are adapted to be underwater, and almost always, the water is oxygenated so the plants don't "drown".

bottom watering might work in a container if you fill it and keep it empty after no more water is being channeled up.. but if you keep water in it, the plant will inevitably have problems if the water just stays there,. no only that, but it will likely start to smell like sh*t/sewer.. after that, the soil will likely become anaerobic.

I don't think that hydroponic roots are biologically different than soil roots. No "adaptation" going on. Same roots. It is well understood though that hydroponic root systems are smaller and denser for a given sized plant, because the roots don't need to stretch to reach hard-to-get nutrients. The reason roots die in overly wet soil is root rot. Root rot is, by the way, a major threat to hydroponic gardeners.

When you take a cutting of a tomato and encourage rooting by immersing it in water, are you developing a different kind of root? Nope. Those roots work fine in soil. It is true, however, that those roots are pretty oxygen starved in non-aerated water.

I'll say again that routine watering from the bottom up is not in the best interest of a plant, for many reasons.

Some may find this article helpful

https://gardening.stackexchange.com/questions/13774/what-is-a-perched-water-table

Dave