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growing houseplants in water vs soil

Posted by brit1 (My Page) on
Sun, Apr 22, 12 at 18:14

Hi, I have many houseplants but a family member is allergic to mold (not sure that my plants have mold, but just in case)so was thinking of growing my plants in pretty containers in water instead of soil. Just curious if they would still help clean the air if not in soil? brit

Follow-Up Postings:

RE: growing houseplants in water vs soil

I would not recommend doing that unless it is a plant that can handle such an environment of which there are few. Please list the plants you are considering for a more concise answer. Mold is not usually an issue unless soil is to wet and the air in your home damp but then mold will be a bigger problem and more of a concern elsewhere in your home.


RE: growing houseplants in water vs soil

Yes, you can.

You can grow most plants in a system called hydroculture, Also called Passive-Hydroponics or semi-hydroponics.

You would basically be growing in water however most plant will still need a media for support. Common support media are LECA, rockwool, Gravel, Sphagnum moss, Coir, sawdust & wood chips. The organic media are generally used for short term planting because they will deteriorate over time. Some people have used sand but it is too small and doesn't allow for enough O2 to reach the roots.

I have used Sphagnum for planting a few years old but the wood and coir turn to a smelly mush sooner then that.

You need to use a nutrient solution for best results but a regular water soluble fertilizer can be used it necessary. Undrained glass or ceramic vessels, plastic tubs and even certain kinds of metal containers are possible plantings.

You can grow species from rain forests plant to cactus in passive-hydro. The water sits in the lower portion of the containers and the roots grow down to it, the plants don't sit in the water.

It is also very important to change the water every 3 or 4 weeks, don't just add to it so there is a bit of ongoing maintenance to it.

RE: growing houseplants in water vs soil

Dellis the system you describe is not the same as the poster asked about "growing my plants in pretty containers in water instead of soil." This is quite different from passive hydroculture and not what this person stated is his/her intent. Why would one grow a desert cactus in a system such as that when most desert cacti need a dry and cold period in order to grow and bloom which under those conditions would kill the roots in cold wet conditions.


RE: growing houseplants in water vs soil

I offered the OP a way to grow their plants permanently in a water culture, without soil. Growing without having soil seemed to be the intent of the question rather than just being able to grow in water.

In passive-hydro you can use any container you want that has the capacity to hold the plants and as long as it will hold fluids, My guess is that that would include quite a few pretty and decorative containers and vessels. With passive-hydro you do not need pumps, air circulation, special lighting or heating. You are pretty much keeping the plants the same as always except in water rather than soil.

Why someone would keep cactus in P-H? I don't know, maybe because you can? It isn't necessary to do so but they will grow that way. The plants don't sit in the water so there is no reason it can't be left to dry and get cold if you feel the need to have those conditions. Folks who grow the plants in some of the various gritty mixes are basically growing with P-H without a reservoir.

RE: growing houseplants in water vs soil

Indoor gardening doesn't produce mold, I can't imagine what one could to do them that would produce it.

Plenty of plants can be grown in just water. Pothos are some of the more common ones. I grow them in clear plastic cups of water in my bathroom to keep some greenery in there. I change the water once in a while & it's just fine. Spider plants seem to grow this way as well.

RE: growing houseplants in water vs soil


i spent a fair amount of time a year or two ago looking into this very question. i wasn't concerned with mold, rather i was looking for a way to have my plants 'perfectly watered' at all times. i read, and experimented, and finally decided on the semi-hydro or passive hydro system that dellis mentioned above. so far, i'm happy with my set up, but i may try to play around with straight water culture in the future.

there is an old out of print book on plain water culture called "The Indoor Water Gardener's How-to Handbook" by Peter Loewer. it's usually available for pretty cheap on amazon or ebay. it is a very small, short book, but it covers some of the basics on issues such as which plants work well, how to keep your water fresh, and such.

to summarize the book, any of the common houseplants that root easily in water can be 'grown' in water culture. specifically, he mentions philodendrons, pothos, aglaonemas (Chinese Evergreens), and dracaenas, as well as some others. he added a couple of pieces of activated charcoal to each vase to help keep the water fresh. and he didn't use much fertilizer because he tended to use clear containers and didn't like to look at algae.

the main reasons that i didn't go with the plain water method is that i couldn't figure out how to properly support large plants, or how to have the plants really grow well. the reason that i put 'grown' in quotation marks in the paragraph above is that plants grown in plain water, even with some fertilizer, won't grow as big and full as they would when grown well in other media. they'll grow slowly, and i didn't want to just have plants that look like "cuttings" if that makes sense.

[i have found some orchid growers who are truly *growing* their plants in only water with fertilizer, but it seems that you have to have algae present for it to work, and i didn't want to be looking at stringy algae in my living room. if you are interested in this growing method, ask and i'll be happy to provide some links.]

i think the easiest thing might be to join the Lucky Bamboo and Lucky Lotus craze. both of these are types of dracaenas. they come already rooted and ready to go. the other nice thing is that the cane area means that the water level can rise and fall a bit between water changes without it damaging the plant. plants such as spathiphyllum can grow well in water but you would need to keep the water right at the dividing line between the roots and the crown or you'll get rot. it would be fairly high maintenance. other good choices would be to root your own canes of any of the other dracaenas, or canes of aglaonema or dieffenbachia.

there is a woman who writes a blog called Gardening on Cloud 9 that covers some of these issues and she makes lovely houseplant displays. her photos are inspiring. i've placed a link below. she uses the word Hydroculture interchangeably for water culture, passive hydroponics, and water crystals.



oh, and regarding mold, anytime there is organic matter and moisture in the same place, you can have mold. even in the passive hydro system dellis menions, you can have mold, though it will be much less than with soil. the ceramic media doesn't mold, because it is inorganic, but all it takes is to have a single root die in the pot, and mold can grow. damp potting soil most certainly contains mold. plain water probably is the only truly mold free growing media. water beads (crystal soil) might also qualify as long as they are rinsed well every once in a while.

finally, if 'low mold' is good enough, and you are interested in passive hydroponics for houseplants, this is one of the better web pages:

Here is a link that might be useful: Gardening on Cloud 9 - Hydroculture

RE: growing houseplants in water vs soil

thank you all so much for your responses, much appreciated. Thanks especially to Nancy :)

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