Turn your polytunnel plan into a seed order

This worksheet organises quantities. It does not choose how many seeds to sow, assess old seed or recommend a crop, sowing method or allowance for losses.

Keep planting positions and seed quantities separate

Start with your bed plan and the exact crop and variety you intend to order. If you use the planting planner, keep its dimensions and chosen spacing with the result. Its count describes a grid; it does not calculate a seed requirement.

Write a separate seed target for each variety, with a note explaining where that decision came from. You may need to check the packet instructions or appropriate crop guidance before choosing it. Leave the target unresolved if you have not made that decision. Do not fill the gap by copying the planting-position count.

Record any extra quantity you have chosen explicitly, with its reason, rather than hiding it inside the packet calculation.

Check what you already have

Match each stock entry to the name and variety on its packet. Keep different varieties on separate lines even when the crop name is the same. A packet you cannot identify should not quietly reduce the order for a named variety.

Record the quantity you are counting towards this plan and how you obtained it. A labelled original quantity does not tell you how many remain after some have been used. If the remaining amount is unknown, write that and resolve it before treating the shopping list as complete.

Decide separately whether stock is appropriate to use. Counting it does not establish that it will germinate.

Copy a worksheet for each variety

Use one record per variety and note the date. This narrow template can be copied into a notebook or spreadsheet.

Use the packet quantity for the exact option you are considering. If a listing gives only a weight, this worksheet cannot convert it to a seed count. If it says the count is approximate, preserve that qualification rather than reporting a guaranteed total.

Worked example: stock changes the order

These are fictional quantities chosen to demonstrate the arithmetic, not a seed recommendation or a description of any product.

Suppose a plan has 40 planting positions. Its owner has separately chosen a target of 55 seeds and recorded 18 seeds to count towards that target. The 15-seed difference between target and positions is an invented choice, not an advised allowance.

The quantity still to obtain is 55 − 18 = 37 seeds. Suppose the fictional packet contains exactly 25 seeds. One packet leaves the arithmetic target short: 18 + 25 = 43. Two packets give 18 + 50 = 68, so the order is 2 packets. That is 68 − 55 = 13 seeds above the chosen target because whole packets cannot be split in this example.

In spreadsheet terms, divide the quantity still to obtain by the stated packet count and round up to a whole number. Here 37 ÷ 25 = 1.48, which rounds up to 2. If the recorded stock already meets the chosen target, the quantity still to obtain is zero and this calculation calls for no additional packets.

Check the list before placing an order

Read the variety names and packet options again after calculating. If an option changes, recalculate with its stated count rather than carrying over the old packet number. Check that the same owned stock has not been allocated to two different plans.

Keep unresolved quantities visible. A line with unknown stock or no stated seed count is a question to answer, not a finished packet order. Once you have chosen what to buy, add the actual quoted cost to your polytunnel budget.

Keep the order reference with the plan. As you use stock, update its recorded balance so the next order starts from the new figure. A growing diary can link that record to what you actually sowed or planted while the stock sheet tracks what remains.