Planter Box Setup in Sandustry: Wet Seeds to Gold

A Sandustry Planter Box setup has four parts: turn dry Seeds into Wet Seeds inside a sealed water chamber, deliver those floating Wet Seeds onto the boxes, let each one grow a Flower, then destroy the mature head with fire to collect 1 Gold and 4 Amethelis. The Planter Box itself sits in the Tier 3 research tree at a listed cost of 2,000 Gold, and it is the natural next step for the Seeds your Kinetic Slag Press emits while it presses burnt residue. The design rule that makes or breaks the farm is containment: wetting, planting, burning, and output clearing each need their own stage so one backed-up pile cannot stop the whole system.

How the Planter Box works

A working flower farm: seeds drop into a sealed water chamber, grow on Planter Boxes, and the harvested heads route to burners or Collectors.

The Planter Box grows a Flower the moment a Wet Seed touches it, and each Wet Seed produces one plant. The official machine page documents one more detail that shapes every layout: Gold and Amethelis are the only solid pixels that can pass through a Planter Box. Liquids and gases are not blocked, while the player is.

That permeability makes the space below the box a natural collection lane. Leave a clear drop path under the boxes so Gold and Amethelis from harvested flowers can settle where you can route them. Test a small crop before building a large array, because you want to see exactly where both materials land on your terrain before committing to it.

Current Early Access footage also shows that a completed Flower can be harvested immediately, and that waiting longer does not increase its yield. The delay that matters is waiting for the head to form, not leaving a mature crop standing. That is why later sections focus on moving seeds and clearing outputs rather than on timing the harvest itself.

Step 1: Make Wet Seeds in a contained chamber

A dry Seed becomes a Wet Seed the instant it touches a single pixel of Water, absorbing it. Build a small, fully enclosed water chamber and route dry Seeds into it rather than pouring water over the Planter Boxes. A sealed pocket stops incoming Seeds from spreading through your main reservoir or drinking more of the farm's water supply than intended.

Fill the chamber through a Pump, Pipes, and a Liquid Vent if you have the fluid tech, or just fill a small pocket manually for the first test. One community-tested rule from the Steam forums: you rarely need more than about 4 tiles of water depth, and the outside water inlet should sit low to prevent overflowing. A shutoff point on the seed line lets you stop the farm without dismantling the water section.

Keep this seed branch separate from the rest of your factory before it reaches the water chamber. If the farm hangs off your main Gold chain, the Kinetic Press can supply the Seeds, but divert them before they mix with stored Gold or other press outputs.

Step 2: Move floating Wet Seeds to the boxes

Wet Seeds float, so they will not sink onto a planting lane by themselves. Give the chamber a controlled exit and guide them outward with its shape, push them through a static pool with Clearing Frames, or catch them with a Launcher after they leave the water. You can prove the whole cycle with nothing but water, one Planter Box, and a manual Flamethrower; the transport machinery is for making it continuous.

Two filter tricks from the community keep the wetting stage honest. Put a filter at the top of the chamber set to let dry Seeds fall back down if they missed the water, plus a second one after the exit for insurance. A wall filter also stops Wet Seeds from climbing back up the chamber wall under heavier bursts, which is a common source of phantom buildup.

There is an honest trade-off between wetting methods. Drip-feeding water onto Seeds with a low inlet is simple and compact, while Clearing Frames are slower per tile but handle higher throughput, and each approach has defenders in the community. Pick one, watch a full batch travel the chamber, and only then scale the seed input.

Step 3: Enclose the growing chamber

Enclose the growing area with solid blocks before opening the Wet Seed input, because plants do not respect your factory's boundaries. Community layouts also use Lights as compact boundaries, while filters are dependable for harvested materials but weak as the wall around active growth. One Steam poster's warning is worth repeating: enclose it and let no Flowers out, or you risk an overrun growing area that keeps sprouting from escaped material.

If Flowers seem to regrow forever, stop all new Seed input first. A visually small growing point can represent a much larger accumulated Seed supply stacked behind it. Let the existing plants form heads, destroy the mature Flowers, clear the products, and repeat until no new growth starts; burning only unfinished stems interrupts growth without producing a useful harvest.

Step 4: Burn mature heads and split the outputs

Destroying a mature Flower head releases its 1 Gold and 4 Amethelis, and fire is the standard tool. Start with a manual Flamethrower while commissioning the farm. For automation, unlock thermal buffers and the Pyro Dispenser: mount the dispenser so it fires across the crop, feed it from an adjacent thermal buffer (which you charge with the Flamethrower), and it emits flame bursts at a regular interval to harvest continuously. A contained lava basin near the crop can support automated burning too, but isolate it from water and loose factory material.

Split the harvest immediately rather than letting it settle. Route Gold toward research storage with a Gold filter, and give the much larger Amethelis stream its own belt, drop, or buffer. An Aerokinetic Fan or a wide free-fall lane clears the light petals before they blanket the growing area, since a petal pile on the boxes is a logistics warning, not a sign you need more Planter Boxes.

Batch first, continuous later

Commission the farm in batch mode before attempting a continuous one. Feed a small amount of Wet Seed, close the input, let every plant mature, burn the finished heads, and clear both outputs before starting again. Batch runs make hidden Seed buildup easy to detect, which is the single most useful debugging property this farm has.

A continuous farm adds controlled transport (Clearing Frames or launchers), intermittent fire, and reliable output removal so it runs without reopening the input. Only switch after the Wet Seed chamber and the harvest exits have each been tested separately. If either output backs up, return to batch operation until the obstruction is fixed.

Give the Amethelis somewhere to go

Flower farms produce far more Amethelis than Gold by count, so plan its destination before scaling. Amethelis combines with Redsand at a one-to-one ratio to produce two Voidbloom. It also opens the Energy route: steam drying produces Dry Amethelis, burning that produces Florin gas, and cooling condenses it into Florinol. Our pages on growing Flowers, finding Wet Seeds, and Amethelis sources cover those follow-on chains.

Troubleshooting the common failures

Most planter failures trace back to one of a few causes. If nothing grows, the input was dry Seed rather than Wet Seed, or the seeds missed the box entirely; inspect the chamber and test one Wet Seed by hand. If Wet Seeds sit in the chamber forever, their floating movement has no controlled exit, so change the chamber shape or add Clearing Frames and a Launcher.

If Flowers burn without producing resources, fire is reaching unfinished growth; increase the distance or delay between planting and ignition. If Gold never reaches storage, the mixed output is not separated yet; add the Gold filter before the common line backs up. And if Pyro harvesting stops, test with a manual Flamethrower first, then inspect the dispenser and its thermal buffer separately.

Sources and version notes

This guide reflects Early Access v0.5.x as of August 2026. The Wet Seed-to-Flower interaction, the Tier 3 placement, the 2,000 Gold cost, and the Gold/Amethelis permeability come from the official Sandustry wiki pages (Planter Box, Research, Wet Seed, Flower) as summarized in collected sources checked August 16, 2026; the official Research page is marked work in progress, so treat the tier and cost as dynamic and confirm them in your in-game Research tab. The 1 Gold plus 4 Amethelis yield and the no-benefit-to-waiting behavior are from current Early Access gameplay footage, not an official wiki table, and no exact maturation time is documented anywhere official. The 4-tile water depth guideline, the wall-filter trick, and the drip-feed versus Clearing Frame trade-off are individual player reports from the Steam forums, not independently verified.