Quick Answer: If you already know what you want to cover your greenhouse with — or want to switch covers by season — a frame-only kit is the cheaper way to get there. Agfabric’s rust-free steel hoops (roughly $20–45 for a 6-pack, depending on length and diameter) are the best overall pick for a standard raised-bed or row-tunnel frame. Gardzen’s 24-piece hoop kit (well under $30) is sized specifically for raised beds, and VIVOSUN’s 5FT hoop kit is the cheapest single-bed option. If the end goal is a rigid polycarbonate panel rather than plastic film, a heavier 9-hoop steel kit built for that exact upgrade path is the frame to buy instead.
A frame kit only makes sense once you know what’s going on top of it — pair it with our greenhouse plastic picks for film, or greenhouse cover replacement if you’re recovering an existing structure.
Greenhouse frame kits by the numbers:
- $20–$45 — the going range for a 6-pack of rust-free steel hoops alone (no cover included) at current Home Depot listings for Agfabric’s hoop line, depending on hoop length and pipe diameter.
- 1–4 years vs. 10–15 years — the rated lifespan of standard polyethylene row-cover film against rigid twin-wall polycarbonate glazing, per greenhouse-supply lifespan guides — the same cover-material gap covered in our greenhouse plastic guide, and the reason a frame-and-cover approach lets you upgrade the cover alone as it wears out.
- Under $30 — what a 24-piece Gardzen raised-bed hoop kit typically runs, verified against current Amazon listings, making it one of the cheapest ways on this entire site to add frost protection to an existing bed.
Best greenhouse frame kits at a glance
| Frame Kit | Best for | Material | Cover included? | Price |
|---|---|---|---|---|
| Agfabric Steel Greenhouse Hoops | Best overall | Rust-free coated steel | No (some listings bundle film) | ~$20–45 / 6-pack |
| Gardzen Garden Hoops (24-pc) | Best for raised beds | Rust-free fiberglass | No | Under $30 |
| VIVOSUN 5FT Hoops Kit | Best budget | Plastic-coated steel | No (PE cover version also sold) | Check current price |
| 9-Hoop Steel Kit (BYO polycarbonate) | Best for a rigid panel | Solid steel, heavier gauge | No — sized for a rigid sheet | Check current price |
1. Agfabric Steel Greenhouse Hoops — Best Overall
Agfabric Rust-Free Steel Greenhouse Hoops (6-Pack)
- Rust-free steel hoops sold in multiple lengths and pipe diameters, so you can match hoop height to the raised bed or row you're covering.
- Most listings sell hoops alone; some bundle a matching row cover or greenhouse film if you'd rather buy both in one order.
- Coated steel construction holds up better outdoors long-term than bare uncoated rebar or conduit.
- Sold through both Amazon and Home Depot, so pricing and availability are easy to cross-check before ordering.
- Works with row-cover fabric, shade cloth, or thin poly film — not rated for a rigid polycarbonate panel.
While you’re pricing out a frame kit and cover separately, it’s worth setting up a free trial of Kindle Unlimited — it’s stacked with season-extension and greenhouse-growing guides if you want a second opinion on cover choice before you order. Sponsored link — we may earn a fee if you sign up. No extra cost to you.
Agfabric is the widest hoop lineup we found — enough length and diameter combinations to fit a single raised bed or a full row tunnel from the same brand. Because most listings sell the hoops alone, confirm before ordering whether your specific listing includes a cover or not; a few bundle row-cover fabric or film, and paying for a cover you don’t need is the easiest way to overspend on this category.
2. Gardzen Garden Hoops (24-Piece) — Best for Raised Beds
Gardzen Garden Hoops for Raised Beds (24 pcs)
- Rust-free fiberglass hoops sized specifically to arch over a standard wooden or metal raised bed.
- 24-piece set covers a multi-hoop tunnel on one bed; a 72-piece set is also sold for covering several beds at once.
- Pairs with row-cover fabric or clear poly sheeting — we cover both the DIY hoop approach and all-in-one alternatives in our greenhouse for raised beds guide.
- Lightweight fiberglass is easy to bend into an arch by hand — no tools required for setup.
- Not built for a rigid panel; this is a fabric-and-film frame, not a structural one.
If you already have a raised bed built and just want frost protection or pest netting over it, this is the cheapest legitimate option on this list. We priced the 24-piece set at well under $30 when we researched the raised-bed cover angle for this site — it’s the same recommendation we make for retrofitting an existing bed rather than buying an all-in-one covered planter.
3. VIVOSUN 5FT Hoops Kit — Best Budget
VIVOSUN Greenhouse Hoops Kit (5FT)
- Plastic-coated rust-free steel hoops sized for a single 5-foot bed or short row.
- Sold both as bare hoops and as a bundle with a PE cover, so check the listing title before ordering if you want the frame only.
- Smaller footprint than Agfabric's lineup — best for one bed rather than a full row of tunnels.
- VIVOSUN also sells a 4FT / 6-piece variant if your bed runs shorter.
VIVOSUN’s hoops are the closest thing to a starter-size option in this category — useful if you’re testing whether a covered bed is worth the effort before committing to a full row of Agfabric or Gardzen hoops across your whole garden.
4. 9-Hoop Steel Kit (Add Your Own Polycarbonate) — Best for a Rigid Panel
Garden Hoops Greenhouse Kit — 9 Solid Steel Hoops
- 9 solid steel hoops plus end caps and stakes, covering roughly 24 feet of tunnel length.
- Built to a heavier gauge than the raised-bed hoop sets above, specifically so it can carry a rigid polycarbonate sheet instead of just fabric or film.
- You supply the polycarbonate — see our greenhouse plastic guide for panel and film options once the frame's in place.
- Made in the USA, with a natural rust-patina finish and a light protective oil coat rather than a painted or plastic coating.
- Best suited to growers who want the rigidity of a hard-panel greenhouse without buying a complete pre-matched kit.
This is the frame to buy if fabric or film was never really the plan — it’s rated to actually hold a rigid panel rather than just row-cover material. Compare it against our hoop house vs greenhouse breakdown if you’re still deciding whether a hoop-framed structure like this or a fully glazed kit makes more sense for what you’re growing.
How to choose a greenhouse frame kit
- Decide on the cover first, then buy the frame to match. Fabric and thin film work with any hoop gauge; a rigid polycarbonate panel needs the heavier 9-hoop-style frame, not a light raised-bed set.
- Check whether the listing includes a cover before you order. Several Agfabric and VIVOSUN listings bundle row-cover fabric or PE film with the hoops — buying a bundle when you already own a cover is wasted money.
- Match hoop count to bed length, not just bed count. A single 24-piece Gardzen set covers one multi-hoop tunnel on one bed; longer rows need proportionally more hoops or a longer kit.
- Confirm rust protection. Coated or plastic-sleeved steel, or fiberglass, holds up outdoors for years; bare uncoated metal from a general hardware aisle will rust within a season or two.
- Don’t forget anchoring. A bare frame with a lightweight film cover catches wind like a sail — see our greenhouse anchor kit picks if your frame will sit somewhere exposed.
The bottom line
If you want the flexibility to swap covers by season or you’re retrofitting a bed you already built, Agfabric’s steel hoops are the best overall frame kit — widely available, rust-free, and sized to fit almost any bed. Gardzen’s 24-piece kit is the cheapest dedicated option for a single raised bed, and VIVOSUN’s 5FT kit works if you just want to test the idea on one short row. If a rigid polycarbonate panel is the real goal, skip the light-duty hoop sets and go straight to a heavier 9-hoop steel kit built for that load. Want the peaked gothic profile instead of a round curve for better snow shedding, our best gothic arch greenhouse picks cover fully packaged Cypress-and-polycarbonate kits built to that shape. Whichever frame you land on, see our greenhouse plastic and greenhouse cover replacement guides next — the frame is only half the build.