Terra cotta v/s plastic pots

Discussion in 'Houseplants' started by Saproxylic, Oct 19, 2016.

  1. Saproxylic

    Saproxylic New Seed

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    I have repotted a lot of my plant babies from the plastic pots where I was rooting them into permanent unglazed terra cotta pots and have noticed that the potting mix seems to dry out so much quicker in terra cotta pots, whereas in plastic soil stays damp and stodgy pretty much forever. This makes me worry about the plants left in plastic pots, as it seems that even though I'm using the same potting mix, the microclimate in plastic pots might not be the best, also the soil on top of plastic pots seems to start accumulating salt sediments (the thin white frosting on top) in less than a month, nothing like that happens in terra cotta. Should I be striving to repot all of my green friends in terra cotta asap?
     
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  3. toni

    toni Mistress of Garden Junque Staff Member Moderator Plants Contributor

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    Do the plastic pots have a drainage hole? If not, you need to make one. They can stay in plastic but cut way back on the watering. Don't water on a schedule, water only when the soil is dry to about 2 inches down.
    But for now you need to transplant them to dry soil before the roots rot. Terra cotta pots are good too, but most are unglazed and that is why they dry out quicker, the water is evaporating through the unglazed clay.
     
  4. Ronni

    Ronni Hardy Maple

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    Yeah, pretty much what she said ^^ ;)

    Even though they dry out more quickly, I still prefer the terra cotta pots, though I use both equally. One thing about the plastic pots, at least with the bigger plants, (I have a lot of houseplants) is that they're much lighter to move around than the terra cotta ones which are heavy even when empty.

    And just as an aside, I get that thin white coating even on my non-plastic pots...though now that I think of it, it's more the glazed terra cotta than the unglazed. So I guess it has to do with how much the soil and roots can breathe.
     
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  5. purpleinopp

    purpleinopp Young Pine Plants Contributor

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    Absolutely, unglazed clay pots help roots have access to more oxygen, as well as allow soil to dry more quickly because they are porous and allow for air exchange. Up to a certain size, (due to the extra weight of the clay pots,) it's my goal to move all of my smaller plants to unglazed clay pots.

    Roots need oxygen & moisture at the same time to function.
    Just air = shriveling. Just moisture = suffocation & rotting. Either will cause root death and desicated foliage because the roots have been unable to deliver moisture. Having to let soil dry, as if ones' tropical jungle plant was a cactus, is an unnecessarily stressful coping mechanism for non-desert dwelling plants in soil without enough oxygen for the roots to stay healthy when it is moist and can lead to premature loss of older leaves and in extreme cases, dry shriveled roots/dead plant.

    The ability of roots to be able to function properly depends greatly on the soil structure/texture, which can change over time. Potting soil tends to be very dense, mostly peat, with very little air in it. Any kind of organic ingredients decompose into smaller bits over time, and roots fill air spaces over time as they grow through soil. Replacing soil periodically is usually necessary to keep plants healthy because of these reasons. A more porous, chunky, airy soil (like cactus/palm, if one is buying bagged,) can have more air in it even when it is moist because there is space between the particles. When there are tiny particles of any kind in a pot, such as peat, sand, silt, clay, they filter into all of the tiny spaces in a pot, eliminating the air. "Overwatering" is the label and manifestation when roots have suffocated and/or rotted, combo of both. Over time, organic bits decompose into smaller bits, so even the "best" soil, if it has organic components, will need to be replaced when this happens. The speed at which this happens depends on many variables, but on average, about 1-3 years.

    What is necessary for plants to stay alive is for their roots to not rot, which can happen so easily in a pot with dense soils, like ground dirt, or bagged mixes of predominantly tiny particles of peat, (or to simply shrivel from simply never getting any water.) Having very little soil around the roots would make the soil dry more quickly, and for even the most dedicated plant-overwaterers to not rot the roots of their plants. This is not ideal, since most non-cactus plants are stressed by dry conditions, it's just a way of coping with soil that has little air in it when moist.

    Negative experiences in regard to potting-up, where an undisturbed root ball is placed into a bigger pot with more soil around it, vs. doing a repotting, as described below, can give rise to old wives' tales about plants not liking to be repotted/disturbed. Potting-up a root-bound plant that has roots surrounding the outside root ball often lead to this negative experience because those roots had adapted to accessing oxygen around the outside of the root ball and surrounding them with more dense, soggy-but-airless potting soil will likely lead to suffocation.

    The reason bonsai masters are able to keep potted entities alive for hundreds of years is because they care for the roots by trimming them and changing the soil. A plant grows from the roots-up, so if the roots are not healthy, gorgeous foliage will decline &/or no flowers can form. When you unpot a plant and find a pancake of roots at the bottom, chopping that off will give roots a chance to grow normally again for a while and will make removing the old soil easier.
     
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  6. Saproxylic

    Saproxylic New Seed

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    Thanks guys! My plastic pots have plenty of drainage holes (like 6 or 8 in the bottom of the pot), I suspect I might have compacted the soil too much while potting though, and simply worked with a lighter hand while potting in terra cotta pots (I guess small cuttings aren't like trees and don't need a good stomping around them while planting, I'm still learning).

    I think I will slowly replace the plastic pots with terra cotta a few at at time and not sweat it too much, as all the plants seem to be growing relatively happily at the moment.
     
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  7. mart

    mart Strong Ash

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    You can slow the evaporation rate for terra cotta pots by painting the top third and the bottom third of the pot. Leave the middle third unpainted. You willl just have striped pots. But better yet when using terra cotta is to soak the pot and all at least an hour when you water the plants. Allow the pot to absorb water and that slows down evaporation from the soil !! Over watering is much worse for most plants than under watering.
     
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  8. Saproxylic

    Saproxylic New Seed

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    Yey, all but one plants in terra cotta now! I hope they will be happy!
     
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  9. Clay_22

    Clay_22 In Flower

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    Plants in terra cotta need to be watered more. Water evaporates much quicker in them.
     
  10. Doghouse Riley

    Doghouse Riley Young Pine

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    "Each to their own," as they say.
    I don't like plastic pots, nor do I like decorated terracotta pots, I consider them unattractive and detract from their contents.

    We've a couple of dozen 34cm Apta Cambridge glazed pots, in dark green, roses in most of them.
    But recently I've been trying something else. A plastic pot in a glazed one.

    This is the largest pot they make,41cms, we have three of them. One at each end of the patio steps.

    This one is by the front door.
    It means we can ring the changes I also think being in a double pot might protect the contents from extreme temperatures.


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    The smaller ones all sit in plastic pot movers. I drilled a hole in the bottom of each, which lets excess water out during the winter.
    For the summer I put a dab of silicone over the hole, so they retain water, less chance of them drying out on our patios.

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  11. Pacnorwest

    Pacnorwest Young Pine

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    Riley your pots are so nice and compliment all the plants very nice. In a few more weeks they will all be overflowing with blooms and foliage . Just what we all plan for all winter. You have an amazing garden . Perfect to watch the season put on a show. Soon the azaleas and rhody’s will be the main event showing up the past stars as each plant begins a new journey to bloom. :smt026
    Just like the fountain it is a beautiful accent and placement is perfect which adds peace and tranquility to the experience pictured.
    :smt055:smt055:smt055 Your beautiful garden . Thank you for sharing your amazing gardening talents.
     
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  12. Doghouse Riley

    Doghouse Riley Young Pine

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    Thanks for the kind words.

    There's a story behind the fountain.

    When I told my wife that because of the leak I was going to close down the koi pool and have it filled in and paved over after thirty years, she asked if we could have a water feature on the patio next to the French windows. The problem with water features is the power supply. I don't like exposed cables and I'm not fond of anything solar.

    The koi pool originally had a pump sump connected to the bottom drain and housed two pumps, one to feed the filter and one to an outside drain for purging. The pumps' mains cables that led to the filter room in the back of the garage via some conduit under the path.

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    You can see it here at the head of the new patio.

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    So I asked her if she'd settle for one at the top of the new patio. Fortunately she was happy with that.

    All I needed was a round concrete stepping-stone instead of the original plastic sump lid, with a hole drilled through it for the power supply via one of the cables that were originally for the pumps.

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    The biggest problem was finding a suitable fountain. None of the area garden centres had anything suitable, not even Bents, they were mostly all naff plastic. But I found this firm in America, Massarelli, that made a huge range of "stone" fountains.

    Fortunately at the time I found a dealer in England. I phoned them and they said they got a container delivered of assorted Massarelli fountains once a year and one was due in shortly and had the one we wanted in it. A Bella.

    In actual fact it arrived only a few days later and ours was delivered just over a week later. On a pallet in a big cardboard box wrapped in thick re-cycled coffee bean sacks, with a few free coffee beans amongst them. It was a pain to install as it weighed 157lbs. I had to fashion a plinth for it out of concrete mix. But £500 well spent. It has a drain hole, so it's easy to clean out when required.

    There's no water in the sump under it. I blocked up the 4" pipe in the bottom that is connected to the pool's bottom drain, with concrete

    The fountain had a low voltage adaptor connected to it. So I cut that off.
    I used one of the pumps cables to drag a new cable back from the garage to the sump and connected it to the fountain's cable. There's a recess under the fountain to house the adaptor. So the connection is under there.
    The fountain's adapter is fixed to one side of the garage consumer unit and only low voltage goes through the cable to the fountain.
    Mains power and water aren't a good mix.

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    The fountain is operated by one of these four switches behind the lounge curtains. They are connected to an armoured multi-core cable that goes under the concrete raft under the patio to the garage consumer unit. The other switches control all the other lights in the garden. But we don't turn them on that often. They are all on the garage supply. The power comes one way down one wire from the garage to the switches and back via others when they are turned on.

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    Last edited: Apr 26, 2023
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  13. Pacnorwest

    Pacnorwest Young Pine

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    Riley that is quite a story. I know what ya mean about wires/cables stretching everywhere. It can be a messy/tripping issue. It was worth all the planning and implementation. Something to look foreword to every day :)
    I would hide all the cables under grass fortunately had that choice. Now in sunny areas I use solar pumps in the ponds and bird bath. Water features adds sound and a peaceful ambiance.
     
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