How many stems for a posy workshop? Spares, bunch splits and late changes — worked by hand
This free guide works through a fictional two-session posy class, the Willow Lane posy day, using only arithmetic you can do on paper or in a spreadsheet. It does not include any software. All names and numbers are invented.
1. The recipes and bookings
K1 Garden posy per seat: 3 garden rose (GR), 5 spray rose (SR), 3 snapdragon (SN), 4 eucalyptus (EU), 5 waxflower (WX). K2 Petite posy per seat: 3 SR, 2 EU, 3 WX. Garden roses come in bunches of 12; everything else in bunches of 10.
Session S1 (10:00): 10 K1 seats and 1 demo set for the tutor. Session S2 (14:00): 6 K1 seats and 4 K2 seats. Policy: one spare set for every 5 seats, rounded up, per session and kit.
2. Sets per session
| Session / kit | Seats | Spares (seats ÷ 5, rounded up) | Demo | Sets |
|---|---|---|---|---|
| S1 K1 | 10 | 2 | 1 | 13 |
| S2 K1 | 6 | 2 | 0 | 8 |
| S2 K2 | 4 | 1 | 0 | 5 |
3. Stems needed and whole bunches
Multiply sets by stems per seat and add up. Garden rose: 3 × (13 + 8) = 63. Spray rose: 5 × 21 + 3 × 5 = 120. Snapdragon 63, eucalyptus 4 × 21 + 2 × 5 = 94, waxflower 120.
| Variety | Need | Bunch | Bunches (rounded up) | Stems bought | Leftover |
|---|---|---|---|---|---|
| Garden rose | 63 | 12 | 6 | 72 | 9 |
| Spray rose | 120 | 10 | 12 | 120 | 0 |
| Snapdragon | 63 | 10 | 7 | 70 | 7 |
| Eucalyptus | 94 | 10 | 10 | 100 | 6 |
| Waxflower | 120 | 10 | 12 | 120 | 0 |
4. Splitting bunches between sessions
Prepare S1 first. S1 needs 39 garden roses (30 for seats, 9 for its 3 spare/demo sets): open 4 bunches (48 stems), take 39, carry 9 loose stems. S2 needs 24: use the 9 loose stems first, then open 2 more bunches for the other 15, leaving 9. Each session gets one bucket per variety for seats and one combined “spares & demo” bucket — 12 labelled buckets in total.
5. Late changes on the same stock
After ordering, S1 loses 2 seats (8 left) and S2 gains a K2 seat (5). New needs are 57 / 113 / 57 / 88 / 113, all within what was bought. Because the stock is unchanged, the change can be made by moving stems: 3 spray rose, 2 eucalyptus and 3 waxflower move from S1's seat buckets to S2's; the other freed stems (GR 6, SR 7, SN 6, EU 6, WX 7) go back to the spare pool. Check your actual buckets before moving anything — these are planned figures.
6. A short delivery
Only 100 of the 120 waxflower stems arrive, but the revised plan needs 113: you are 13 short (two more bunches would cover it). Here the tutor decides to swap, in K2 only, 3 waxflower for 2 snapdragon per seat — for every K2 seat, spare and demo set. K2 now has 6 sets (5 seats + 1 spare), so waxflower drops by 18 to 95 (5 left over) and snapdragon rises by 12 to 69 of 70 (1 left over).
Because the waxflower stock itself changed, the old buckets may not exist as planned. Rebuild the buckets from the revised plan instead of trying to move stems you never received.
Every figure is listed in EXPECTED-RESULTS.md; the CSV files describe the same class. Whether a substitution is suitable is your design decision — this guide only does the counting.