Does The Pot Matter To The Plant?

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    Container size is important

    The container size seems like it wouldn’t be important unless it’s too small, but that’s not the case. Container size will directly affect plant size by limiting root growth. A tomato plant in a 10” pot will not grow as large–everything else held constant–as a tomato in a 15” pot. The latter holds three times as much soil. Remember, the plant above ground is a reflection of the plant structure below.

    The amount of soil held in the pot vs. the plant size will affect soil moisture levels. A plant in a too-small container will quickly use up the available moisture in the smaller soil volume. You’ll have to water more frequently, and the plant may experience dehydration stress.

    But that doesn’t mean planting a tiny plant in a large pot is a good idea. If the plant can’t use the water in the large volume of soil, that soil may stay perpetually damp, leading to potential fungal issues that could ultimately prove fatal.

    If you’ve seen advice for houseplants about repotting, and choosing a new container only one size larger, this is the reason. Too large a pot can cause problems. That said, it’s OK to plant a tomato or other seedling in a larger pot it will soon grow into. Just watch the soil moisture level.

    What’s the pot made out of?

    Pots for houseplants, outdoor patios, and deck gardens can be made from just about any material, from plastic to concrete, terra cotta, wood, or ceramics. If you look at my seed starting room, you might even find a few upcycled cottage cheese containers… However, not all materials are well-suited for all plants.

    Terra Cotta

    Beautiful, traditional, and porous, terra cotta pots are also known as clay pots. You probably recognize their rusty orange color. Terra cotta pots allow moisture and air to transfer, which can be an advantage. Plants that enjoy less moisture, like many Mediterranean herbs–rosemary, lavender, oregano, thyme–will do well in terra cotta pots and they’ll look great. For plants that like consistently moist soil, choose another material.

    Plastic

    Pots made from plastics are inexpensive and readily available. They run the gamut from the black nursery pot your hydrangea came was sold in to molded and upscale imitations of more expensive materials.

    Plastic pots are lightweight and easily cleaned and sterilized for reuse (they don’t have to be single-use). They are also inert and impervious to water, so they won’t dry as quickly as a clay pot. Plastic pots are probably the most commonly used type of container for home gardeners.

    Concrete

    Many large planters are made from concrete, either natural-colored or dyed. If treated correctly, these can be very sturdy containers with long useful lives. If you are adventurous, you can also DIY your own shapes and sizes, making them a fun way to express yourself.

    Concrete containers are porous, and may darken when watered and lighten as the soil dries. Their mass can be an advantage for tall plants that catch the wind but it makes them difficult to move around.

    Wood

    Planters made from wood can be gorgeous and rustic. Many wooden half-barrels, traditional window boxes, and homemade planter designs are available. Wood will absorb moisture from the soil and will likely stain over time. It’s also harder to clean. However, it can make an economical choice for large homemade DIY planters and is easier to properly discard at the end of life. Ensure to plan for drainage when designing home-built planters. Rot-resistant woods like cedar, cypress, or white oak will last longer.

    Ceramics

    Beautiful glazed ceramic pots are more common for smaller houseplants but can also be found in larger sizes. Ceramic pots typically are impervious and won’t breathe. Beware, many ceramic pots are intended as a decorative cover for a plastic pot and won’t have a drainage hole. I’ve fallen for this trap before, not paying attention until my plant looked ill from sitting in water-logged soil. Check for drainage holes before you buy, or know in advance you’ll have to pay closer attention to soil moisture levels in that pot.

    Drainage In Containers

    We’ve been talking about drainage a bit, and you already know drainage is necessary for potted plants, whether in the house or outdoors. However, it’s easy to overlook. Some pots have perforated holes that must be punched out with a screwdriver or other tool. Others have no holes, especially if you recycle a vessel from another use, like an old teapot or galvanized bucket from the thrift store. In that case, you’ll need to create drainage holes yourself.

    Adequate drainage means that water can freely leave when there is too much to be held by the soil. If not, a rainstorm or overzealous watering can make a lake in the bottom of the pot.

    Soggy soil doesn’t hold oxygen, which plant roots need to respirate and live. Without it, just like us, they drown. Anaerobic conditions (low oxygen levels) also encourage many “bad” types of bacteria to thrive at your plants’ peril.

    Check those drainage holes, especially if the soil seems to stay wetter than it should, based on the watering frequency.

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