Three numbers and a year of lead time
The requirement is straightforward. Take the cuttings you need to stick, divide by what one stock plant gives you in a season after grading, and round up. What makes it awkward is the calendar: the block that supplies next winter has to already be in the ground and already be big enough, and if the arithmetic says you are short there is no way to fix it in the same season.
On the numbers the form opens with, a stock plant giving 25 cuttings per harvest across 2 harvests yields 50, and at 85 percent usable after grading that is 42.5 usable cuttings per plant per season. Ten thousand cuttings needs 235.3 plants, which rounds to 236, and a 10 percent margin takes it to 259. A block of 150 plants supplies 6,375 usable cuttings — 3,625 short, or 36 percent of the requirement.
Grading loss is not a rounding error
The share of harvested material that is actually usable does a lot of work here and it is the input people leave at 100. Material comes off the block the wrong length, the wrong maturity, damaged, or simply too much of one and not enough of another. If your real figure is 70 percent rather than 85, the same block of 150 plants supplies 5,250 rather than 6,375, and the requirement goes from 259 stock plants to 315. That is a difference of 56 plants and around 300 square feet of block, decided by an input most people never measure.
Measuring it is a morning of counting. Take one harvest, count what comes off, count what actually gets stuck, and divide. Do it once and you have a figure for your own block that beats every assumption on this page.
Ground the block takes
Stock plants at 30 inch centres on offset rows occupy 779.4 square inches each, or 5.41 square feet. Two hundred and fifty-nine of them is 1,402 square feet of plants, and with 20 percent for lanes and edges the block is 1,682 square feet — about four hundredths of an acre. Set the same plants on a square grid instead and the block becomes 1,943 square feet, because a square grid gives each plant the full square of the spacing rather than 0.866 of it.
| Grading share | Usable per plant | Stock plants with margin | Block at 30 in offset |
|---|---|---|---|
| 100% | 50.0 | 220 | 1,429 sq ft |
| 85% | 42.5 | 259 | 1,682 sq ft |
| 70% | 35.0 | 315 | 2,046 sq ft |
The harvest count is the biggest lever, and it is not free
Going from two harvests to three takes the requirement from 259 stock plants to 173 — a third of the block, gone. Going the other way, one harvest a season needs 518. The calculator shows both because the size of the effect is worth seeing.
What it will not tell you is how many harvests your plants will actually stand. How hard a block can be cut, how often, at what time of year, and whether it recovers, are questions about specific plants in specific conditions, and they belong to your own records, your propagation reference, or your cooperative extension service. This page states nothing about any of it. It also states nothing about hormone, fertiliser or any other product, and it has no opinion about whether the block will perform.
One legal point that is not arithmetic at all: propagating a plant that is patented or sold under a trademarked brand is a matter between you and the rights holder, settled by the licence and not by anything here. Whether your operation needs a nursery licence, and what may be shipped where, are state agriculture department questions.
Once the cuttings exist, the bench capacity calculator tells you how much bench they need and the stage calculator tells you what they become.
Questions people ask
How many cuttings will one stock plant give me?
This page does not know and will not guess. It varies by species, by the age and size of the plant, by how hard it was cut last time, by the season, and by what counts as a cutting in your operation. The only reliable source is your own count from your own block, and failing that your cooperative extension service or the propagation reference you work from. The field exists precisely so that the number is yours rather than one invented here.
Should the margin cover losses in the stock block itself?
That is what it is for, along with a harvest that simply comes in light. Stock plants die, get damaged, or come out of a winter in no state to cut. Ten percent is the placeholder in the form. If your block has a history you can do better: work out what share of it you replace in a normal year, and use that. The margin is applied to the bare requirement before rounding, so the two roundings do not stack.
Why does the block come out smaller on offset rows?
Because an offset layout gives each plant a hexagonal share of ground rather than a square one. At the same centre-to-centre distance that is the spacing squared times 0.866, so 13.4 percent less ground for identical spacing between neighbours. It is the same reason a stack of pipes settles into a triangular pattern. The only cost is that rows no longer line up in both directions, which matters if you are running a header down the block or driving anything through it.
Can I use this to work backwards from a number of saleable plants rather than cuttings?
Not directly, and it should not. The losses between sticking and selling belong to the stages, and the potting-up stage calculator is where they are handled. Run that first with your survival shares, read off how many you have to start with, and bring that number here as the cuttings needed. Splitting it that way keeps each set of assumptions in one place instead of compounding them silently.
Does the block area include room for working around the plants?
Only through the access allowance, which is a flat percentage on top of the plant area. That is a crude model of a real block, which has lanes in one direction and not the other and usually a headland at each end. If you have an existing block, measure it and back out your real overhead: divide the fenced area by the plant area you get from the spacing here, and use that percentage instead of the placeholder.