A good planter box is basically a tiny real-estate investment for your plants: you’re buying them better drainage, softer soil,
fewer weeds, and a front-row seat to sunlight. And when a popular option like the Three Posts planter box pops up
at around 30% off at Wayfair, it’s the gardening equivalent of finding guac that doesn’t cost extra.
But here’s the thing: a “deal” is only a deal if the planter fits your space, your plants, and your patience level. In this guide,
we’ll break down what makes this style of Three Posts planter box so buyable, how to sanity-check the discount, what to grow in a
long-and-narrow bed, and how to keep your new garden from becoming a soggy dirt casserole.
Why This Three Posts Planter Box Keeps Showing Up in Carts
Three Posts is known for practical, home-friendly outdoor pieces that lean “classic” rather than “NASA prototype.” The planter box
people talk about most is a rectangular wooden planter designed for patios, balconies, and small backyardsoften in
sizes like 40" long × 12" wide × 12" high (with other size options depending on the listing). The shape matters:
it’s long enough to plant in sections, narrow enough to reach the middle without climbing into it like a tiny raccoon.
Another reason it gets love: it’s typically designed to be quick to assemble (think: basic screws and panels, not a
47-step relationship test). Many shoppers mention they can put it together fast, which is important because the moment a new planter
arrives, your brain immediately says: “We should plant 19 things today.”
And yesthis particular Three Posts planter style is often described as having drainage holes. That’s not a small
detail. Drainage is the difference between thriving herbs and a mint plant haunting your patio like a swamp spirit.
Deal Reality Check: Is 30% Off Actually a Win?
Discounts look dramatic because percentages are emotionally powerful. “30% off” sounds like your wallet just got a promotion. Here’s
how to tell if it’s a real bargain and not just retail theater:
1) Compare the total, not the sticker
For outdoor items, shipping and delivery speed can change the value fast. If you’re paying extra for faster delivery, your 30% off may
quietly become “12% off with a side of regret.” Check whether the planter qualifies for free shipping and whether delivery timing
matters for your planting schedule.
2) Confirm you’re comparing the same size
Listings often show multiple sizes and colors. A headline discount may apply to one size (say, the smaller 40" × 12") while the larger
option is discounted differently. Make sure your price comparison is apples-to-applesnot apples-to-watermelons-in-a-salad-spinner.
3) Decide what “value” means for you
A wooden planter box is usually about convenience and aesthetics. If your goal is maximum longevity with minimal maintenance, metal or
resin beds may last longer outdoors. If your goal is “I want something that looks great on my patio and makes me feel like I have my
life together,” wood is often the vibe.
Planter Box vs. Raised Bed: Same Family, Different Personality
People use the terms interchangeably, but there’s a useful distinction:
planter boxes often have a bottom (and sit on patios or decks), while
raised beds are commonly bottomless frames placed directly on the ground.
Why does it matter? Because it changes drainage, root depth, and how you handle pests.
With a bottomed planter box, you’re managing the entire environmentsoil, drainage, watering schedulelike a plant parent with a
spreadsheet. The upside is control. The downside is: if drainage is blocked, everything turns into soup.
What You Can Grow in a Long, Narrow Planter Box
A 40" × 12" footprint is surprisingly versatile if you plant with intent. Think of it like a subway car: you’re not hosting a dance
party, but you can move a lot of people efficiently if everyone respects the lanes.
Best matches for this shape
- Herb runway: basil, parsley, cilantro, chives, thyme, oregano (group by watering needs).
- Salad strip: lettuces + arugula + spinach (quick harvest, shallow roots, happy in 8–12 inches of soil).
- Flower border: marigolds, alyssum, petunias, dwarf zinnias (pollinator-friendly and patio-pretty).
- Mini “kitchen garden”: a few compact peppers or a dwarf tomato (if the planter is deep enough and you stake well).
- Strawberries: especially if you like the idea of snacks growing at waist height.
What’s trickier (but not impossible)
- Big root crops: full-size carrots, parsnips, and larger potatoes prefer deeper soil and more width.
- Vining plants: cucumbers and squash can work with trellising, but they’ll try to colonize your entire zip code.
Soil: The Part Everyone Underestimates (Until It’s Too Late)
If you want plants to thrive in a planter box, treat soil like the main character. University extension guidance commonly emphasizes
that raised-bed/planter success depends heavily on a quality blend of soil and organic matternot just “whatever bag was closest to the
checkout line.”
Easy, effective soil mix options
-
Balanced blend: roughly topsoil + compost (many guides land somewhere between a 70/30 soil-to-compost mix
and a 50/50-ish split depending on your base soil quality and the bed depth). -
Patio-friendly blend: compost + soilless growing mix (especially useful when you want lighter weight and
consistent texture). Some guidance suggests adding a smaller portion of topsoil only if the bed is deep enough.
The goal is a mix that drains well, holds moisture without becoming a bog, and has enough organic matter to feed plants over time.
If you’re buying bagged products, look for consistent texture (no mystery chunks) and avoid anything that looks like it’s 60% wood
chips unless you’re intentionally building a “forest floor” project.
How much soil do you need?
A quick estimate for a 40" × 12" × 12" planter:
40 × 12 × 12 = 5,760 cubic inches. Divide by 1,728 to convert to cubic feet:
that’s about 3.3 cubic feet of soil mix.
In normal-people terms: that’s often about two to three medium bags of soil (depending on bag size), plus compost if
you’re blending. If your listing is a larger size, do the same math using the posted dimensions. This is the part where you avoid
the classic mistake of buying “one bag” and then trying to stretch it like pizza dough.
Drainage, Liners, and the Art of Not Drowning Your Plants
If the planter has drainage holes, you’re already ahead. But drainage is a system, not a single feature. Here’s how to build it so
water can leave the party when it’s time:
Start with a smart base layer
- On patios/decks: consider a thin layer of coarse material (or a permeable barrier) to keep soil from clogging holes.
- For pest protection: hardware cloth can deter burrowing pests if your planter is placed where critters can access the bottom.
- For weed suppression: cardboard can smother weeds in bottomless beds; for bottomed planters, focus more on drainage than weed blocking.
Should you use a liner?
A liner can help keep soil in place and reduce mess, but it must allow water to drain. If you use a fabric liner, choose one that’s
permeable. If you use plastic, you’re signing up to add drainage holes and monitor water carefully. The safest “rule” is:
never block drainage.
For wood planters, some gardeners also like adding a protective barrier to reduce moisture contact with the wood. If you do this,
keep it breathable and drainage-friendly, and avoid trapping water against the wood.
Wood, Weather, and Longevity: What to Expect Outdoors
Wooden planter boxes look warm and inviting, but weather is undefeated. Sun, rain, freeze-thaw cycles, and constant moisture will
challenge any wood product over timeespecially if it sits wet. Your goal is to reduce the time the wood spends soaked.
Simple ways to help a wooden planter last longer
- Elevate slightly: use planter feet or a small stand so water doesn’t pool underneath.
- Seal the exterior: consider a non-toxic exterior sealant or stain appropriate for outdoor wood.
- Water smarter: deep, less frequent watering beats constant dribbles that keep wood damp.
- Winter strategy: in harsh climates, move it to a sheltered spot or empty and store if possible.
Also worth noting: if you ever compare planters made from different woods or treatments, you’ll see lots of debate about what’s
“food-safe.” University and extension sources generally note that modern pressure-treated lumber has been studied and may leach small
amounts, with low uptake in plants in many findings, but if you’re uneasy, choose untreated rot-resistant wood or add a barrier and
good practices.
Placement: Where Your Planter Box Lives Matters as Much as What’s In It
Before you fill it with soil (because moving it afterward is basically CrossFit), choose the location like you’re picking a seat on a
plane: you want comfort, access, and fewer surprises.
Quick placement checklist
- Sun: most vegetables want 6+ hours of sun; leafy greens can handle less.
- Water access: if you have to drag a hose through three doors, you’ll “forget” to water.
- Level ground: a tilted planter means water runs to one side and your plants live in different climates.
- Surface protection: on decks, consider a drip tray or mat to prevent water stains.
Six Planting “Recipes” for a Three Posts-Style Rectangular Planter
If decision fatigue is real for you (same), here are six proven, beginner-friendly planting plans that fit a long, narrow planter box:
1) The Italian Night Planter
Basil + parsley + oregano + thyme. Add a small trellis at the back for a compact cherry tomato if your soil depth and sunlight allow it.
2) The Salad Bar Strip
Two rows of mixed lettuce + arugula in the middle + green onions at the edges. Harvest outer leaves weekly and keep it going.
3) The Pollinator Welcome Mat
Dwarf zinnias + marigolds + alyssum. You get color, scent, and helpful insects visiting like they pay rent.
4) The Salsa Starter
Compact pepper + cilantro + green onions. Add a small tomato only if you can stake it and you have enough depth.
5) The Tea & Calm Planter
Mint (in a contained section), chamomile, and lemon balmnote that mint spreads like gossip, so give it boundaries.
6) The Strawberry Snack Track
Strawberries + a border of thyme or chives. Keep soil evenly moist and protect from birds if your neighborhood has tiny fruit critics.
Maintenance That Doesn’t Feel Like a Second Job
Watering
Planter boxes dry out faster than in-ground gardens, especially on sunny patios. Water deeply until you see water draining, then let
the top inch of soil dry slightly before watering again (adjust for heat, wind, and plant type).
Feeding
Compost helps, but vegetables and flowers can still need periodic feeding. If growth slows or leaves look pale, a gentle fertilizer
(used as directed) can help. If you want to be extra smart, do a soil test now and thenyour plants will reward you with fewer drama
episodes.
Seasonal refresh
Each season, top-dress with compost, remove old roots, and check drainage holes. If the soil level drops (it often will), top it up.
Raised bed guidance often recommends periodic compost additions rather than starting over from scratch every year.
Who This Planter Box Is Perfect For (And Who Should Pass)
Buy it if…
- You want a tidy, attractive way to garden on a patio, balcony, or small yard.
- You like the idea of quick assembly and a manageable footprint.
- You’re growing herbs, greens, flowers, or compact veggiesnot a full farm-to-table operation.
Skip it (or rethink) if…
- You need maximum longevity with minimal maintenance (consider metal or resin options).
- You want deep-rooted crops and large yields (a larger/deeper bed may be better).
- You hate watering and refuse to change (self-watering planters might be your soulmate).
FAQ: Quick Answers Before You Click “Add to Cart”
Does a 12-inch-high planter work for vegetables?
For many leafy greens and herbs, yes. For bigger plants (tomatoes, peppers, squash), deeper is often easier and more forgivingthough
compact varieties can still work with excellent soil and consistent watering.
Do I need to drill more drainage holes?
If the planter already drains well, probably not. If water pools or the soil stays soggy, then yesimproving drainage is priority one.
What’s the easiest beginner plant for this planter?
Lettuce, basil, chives, and marigolds. They’re forgiving, fast, and rewardinglike the golden retrievers of the plant world.
of Real-World Experiences: What Gardeners Learn After Buying a Deal Planter Box
When people grab a planter box on saleespecially one that’s popular and highly reviewedthere’s a familiar emotional arc that plays
out in backyards across America. It usually starts with optimism, moves quickly into “why is soil heavier than my emotional baggage,”
and ends with either a thriving mini garden or a hard-earned lesson in drainage.
One common experience gardeners share is how a long, narrow planter box changes the way you think about space. At first, it feels like
a lot of room. You stand over it and imagine a lush herb jungle. Then you plant three basil starts six inches apart and realize basil
doesn’t want to be your roommateit wants to be your landlord. The practical fix most people discover: plant fewer things, give them
more space, and use succession planting (add new greens every couple weeks) instead of cramming everything in on day one.
Another frequent “aha” moment is learning that watering is a schedule, not a vibe. Patio planters can dry out fast on hot days,
but they can also stay wet longer than expected after a rainstormespecially if the planter sits flat and water can’t escape cleanly.
Gardeners who struggle early often report they were watering on habit rather than checking soil moisture. The ones who succeed tend to
adopt a simple routine: poke a finger into the soil; if it’s dry past the first inch, water deeply until it drains. If it’s still
moist, walk away like a disciplined adult (rare, but possible).
Then there’s the soil-learning curve. Many first-time buyers fill a planter with a single bag labeled “garden soil,” plant their
seedlings, and wonder why everything looks tired two weeks later. Over time, gardeners report better results after blending soil with
compost and choosing a mix that drains well while still holding moisture. People also learn to top off the planter as the soil settles,
because it almost always does. That settling can make plants look “sunken” and can change how evenly water spreads across the surface.
Assembly stories are another highlight. Some shoppers describe it as a ten-minute win; others say their “ten minutes” included finding
the screwdriver, taking a snack break, and reading the instructions only after they tried to do it from memory. The common thread is
that a straightforward build feels like a victoryand that victory often becomes the motivation to actually plant something instead of
letting the box sit empty like an abandoned New Year’s resolution.
Finally, gardeners often talk about the unexpected joy of a tidy, waist-height harvest. Snipping chives for eggs, grabbing basil for
pasta, or picking a handful of salad greens can make even a small planter feel like a luxury. The lesson many people land on is simple:
a planter box doesn’t have to be huge to be life-improving. It just has to be usedand if a 30% off sale is the push that gets you
growing, that’s a pretty good return on investment.
Conclusion
A Three Posts planter box at about 30% off at Wayfair is a classic “smart impulse buy” if you match it to the right plants and set it
up for success: quality soil, reliable drainage, and a location that gets the sun your crops want. Treat it like a small, controlled
garden ecosystemnot just a decorative boxand you’ll get the kind of low-effort, high-reward gardening that makes you feel suspiciously
competent.