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Best Size Self Watering Planter: How to Choose Small, Medium, or Large for Your Plants
- Eddie Yang
- Sep 24, 2025
- 4 min read
Picture this: you bring home a new plant, set it in a pot that “looks about right,” and weeks later it’s either outgrowing the space or drooping from stress. The truth is, size matters. The right self watering planter doesn’t just save you from constant watering — it gives your plant the room to grow happily with minimal effort from you.
Best Size Self Watering Planter at a Glance:
Small (3") = Best for herbs, succulents, seedlings
Medium (5") = Perfect for houseplants like pothos and spider plants
Large (7") = Ideal for orchids, snake plants, tall greenery
So, how do you know which planter size fits your plant’s needs? Here’s why planter size matters, what works for each type of plant, and how to choose the best self watering pot for both indoor and outdoor spaces.
Why Planter Size Matters for Plant Health
A plant’s roots expand just like our lungs: they need room to breathe. The right planter size controls water balance, soil aeration, and root stability. In a self watering planter, this choice becomes even more important because the reservoir is built to supply steady moisture for weeks.
Too small? Roots become tangled, plants dry out quickly.
Too large? Soil stays wet too long, which may cause root rot.
Just right? The plant has enough space, steady hydration, and grows stronger with less stress.
“As an engineer, I designed Posie Pots so your plants grow stronger with 95% less water.” – Kay Wells said on Fox2 News
Small Self Watering Planter (3" x 3")
If you’re new to plant care, the small 3-inch Posie Pot is the best self watering planter for beginners.
Perfect for:
Herbs (basil, mint, parsley)
Succulents (aloe, echeveria, haworthia)
Starter seedlings
Why choose small?
Small roots don’t need deep soil
Easier to move around windowsills or kitchen counters
Keeps soil from drying too fast with our built-in water reservoir
Medium Self Watering Planter (5" x 5")
The medium 5-inch size is our most versatile and the best selling size.
Perfect for:
Pothos
Spider plants
African violets
Indoor ferns
Why choose medium?
Best balance of soil and water capacity
Great for most indoor houseplants
Compact enough for shelves and desks
Ideal if you’re unsure which size to pick
This is the go-to self watering planter indoor option for anyone looking to grow low-maintenance plants without overthinking size.
Large Self Watering Planter (7" x 7")
When your plant is tall or root-heavy, the large 7-inch Posie Pot is the best choice.
Perfect for:
Orchids
Snake plants (mother-in-law’s tongue)
Monstera
Indoor palms
Why choose large?
Holds 6 cups of water in the reservoir
Supports plants up to 36 inches tall
Prevents tipping or instability for heavier plants
As covered by Fox 2 Studio STL, Posie Pots are available in multiple sizes and designs, each engineered to eliminate overwatering and root rot.
Wave vs. Twisted Square – Which Style to Pick?
Size isn’t the only choice — style matters too.
Wave design → Soft curves, perfect for cozy corners, patios, or indoor gardens
Twisted Square design → Bold, modern, and geometric; great for desks, studios, or minimal spaces
Both come in small, medium, and large sizes, and both can be used as indoor or outdoor self watering planters depending on your space.
Tips for Choosing the Right Planter Size
Still not sure which size to buy? Use these quick tips:
Match plant height to pot size → Your plant should be about 1.5–2x taller than the pot.
Think about growth → Fast growers (like pothos) need medium; tall bloomers (like orchids) need large.
Consider placement → Small for windowsills, medium for tables, large for corners.
Indoor vs Outdoor → Outdoor plants may need larger pots for wind stability.
FAQ: Your Planter Size Questions Answered
Q: What size self watering planter is best for orchids?
A:Orchids do best in our large 7" planter, which provides root depth and consistent hydration.
Q: Can I use a small self watering pot for herbs?
A:Yes. Basil, mint, or parsley thrive in our small 3" planters, especially on kitchen counters.
Q: What’s the difference between small, medium, and large?
Small = herbs, succulents, seedlings
Medium = most indoor houseplants
Large = orchids, snake plants, tall greenery
Q: Is a medium 5 inch self watering planter good for beginners?
A:Absolutely. The 5-inch medium pot is the best self watering planter for beginners, offering balance and easy care.
Q: Can I use Posie Pots outdoors?
A:Yes. Both Wave and Twisted Square designs can work as outdoor self watering planters, as long as they’re kept in shaded or semi-shaded areas.
Ready to Let Your Plants Thrive?
Plant care doesn’t need to be stressful. With Posie Pots self-watering planters, you give your plants steady hydration, healthier roots, and the freedom to grow—while you enjoy watering just once a month.
👉 Shop Posie Pots today and bring home the planter that waters itself.
👉 Claim your first self-watering planter today with Posie Pots—use code WELCOME10 at checkout for $10 off
$50
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$50
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