Planning Planting Quantities

Carol , Carol's Garden

So now you have a good understanding of who your customer is, what they want to buy from you - and you've decided what you want to grow for them.

Think ahead for a moment to when you're standing in the potting shed, with a packet of seeds in your hand. How many do you sow? And when do you stop? This is the same question as deciding how many tulip bulbs to order.

Tulip view of field.jpg

100? 500? 1000? The stakes are high with tulips, margins are tight, and even if you've sourced them well, planted them efficiently, managed to evade all pests and diseases, you can still wipe out any profit at all if you have any left which you haven't sold.

There are no hard and fast rules for planning what to grow. There are so many variables - your type of customer, your growing conditions, weather, pests & diseases, trends and so on. But you need an idea of what to plant and how to use your space wisely. The process of planning starts at the end point (knowing what you need to be able to cut to sell) and works back toward the beginning of the process - standing in the shed with that packet of seeds, or hovering over the bulb website, credit card in hand.


Where to start?

Now that you know what shapes and colours you need and when you need them, it's time to start planning quantities…

You can start in three ways:

1. What you want to sell. You may have a specific target of flowers that you want to sell


market bouquets.jpg

For example, if you agree to supply 30 mixed bunches each week, made up of 18 stems as follows:

• 5 focal flowers

• 5 secondary flowers

• 1 spike

• 7 filler

Then you know you need 150 focal, 150 secondary, 30 spikes, and 210 filler stems each week.

This is easy and neat, but most of us don't have this certainty.

2. Allocating space to particular types. Most of us grow a balance of types of flower - focal, secondary, spikes and filler (or add in trailing, wispy etc according to your customer) and we have a limited amount of space that we can manage. so you can work out how much bed space you want to allocate to each type of flower. If you're just starting out, and have no records to look back on, you can start this way. so if you have 24 beds of equal size, you might allocate them

• 6 for focal flowers

• 6 for secondary flowers

• 2 for spike type flowers

• 10 for filler

But some crops are much more productive than others, and some will be permanent plantings, some just annuals etc etc. So, in reality, you will end up with the third option:

3. A combination of the following elements:

• Going through your records from previous years, how many stems you sold (we will cover this in more detail in module 7)

• Overlay the changes you plan to make - eg changes to customer profile, new ranges, new crops, different colours, tweaks to sowing plans

• Add in any changes to the growing area you have to work with - eg new beds, new covered space etc

• Calculate how many plants you think you will need and how much space you want to allocate to each variety.

How many Ranunculus stems per plant? I’ve seen estimates from 3 to 20.

How many Ranunculus stems per plant? I’ve seen estimates from 3 to 20.

How do I know how many stems I will get from each plant?

Unfortunately, its very difficult to calculate this. If you grow identical varieties in identical conditions, year on year, you will begin to learn what productivity you can expect from a crop. The cultivar producers will have technical specification sheets to tell you exactly what feed to give at each stage of growth and will predict the number of stems of a set length you can expect. This applies to controlled environment, high tech growing. But in reality, most of us have very variable growing conditions and grow different cultivars from season to season. Some flowers are conveniently packaged in a bulb and you get 1 flower per bulb e.g. tulips and gladioli. Most plants will vary with variety, growing conditions and (very importantly) cutting regime. The only way to get a realistic view is to keep records of what you have planted, how many stems you have cut and where and when you had excess or shortages. I tend to plan in ‘beds’ - do I need one bed of ammi, or two, or just half ready at any one time?

Attrition

Now take into account your contingencies or attrition rates. (we'll talk in more about this in future modules) - but its the ‘extras’ you need to sow or plant to cover losses along the way

What is Attrition?
In our terms, it’s the proportion of seeds, seedlings, plants or flowers that you might lose at each stage from sowing to cutting a full crop of first quality flowers

What goes where

Once you know how many plants or how much space you want to allocate to each variety, you can start to plan what is going where, and what to sow.

You need to know:

1. The varieties you want to grow and the distances that they are best planted

2. The size of your beds (and this is one of the reasons we always recommend that all your beds are the same size!)

3. You can then work out how many plants you will get in each bed:

eg., I have beds 1.2m wide and 4.5m long.

• At 6” (15cm) spacing i will get 200 plants per bed

• at 9” (21cm) spacing I will get 100 plants per bed

• At 12” (30cm) spacing I will get 60 plants per bed

• At 18” (50cm) spacing I will get 30 plants per bed

You can work this out either by drawing a scale plan of a bed on some graph paper, or just by laying out small empty plant pots (or anything) at 6” intervals within a 1m length of one of your beds, and then counting up and photographing it. then you can multiply this by the length of your bed in metres. You can probably do it in some graphics package too, if you have access to it. But i’ve only had to do it once, and now I know the answers, so paper is good enough for me.

You will notice that I’ve done two different layouts for each bed. The linear square grid pattern is sometimes easier to manage, but the offset staggered pattern makes better use of space.

You will notice that I’ve done two different layouts for each bed. The linear square grid pattern is sometimes easier to manage, but the offset staggered pattern makes better use of space.

4. So, if I want a whole bed of ammi majus, at 9” spacing, I will need 100 plants. My module trays have 60 cells, so I will sow 2 trays, to allow a few spares too.

Here is a spreadsheet to get you started on your bed planning. You will need to tweak this to suit your own range of crops, but it’s a start point. It doesn't take into account permanent or perennial plantings, just annual/biennial crops. Once you have entered the varieties and planting distances, you can adjust the bed allocations to get the mix of crops that you need. I use this spreadsheet as a basis for adding in special sowing tips, and planned sowing dates too. I keep a copy on the wall in my shed, and try to make notes on it as I go through the year.

So….you’re standing in the shed with the packet of seeds again…..and now you know exactly how many to sow….and where they're going to go….

What if Im using burned weed suppressing membrane?

Of course, if you use weed suppressing membrane with holes already burned, then there will be a precise number of holes and the numbers of plants you need becomes fixed. You may have noticed that the number of plants at 9” spacing is exactly half that at 6” spacing. I now only burn sheets with holes at 6” spacing for my annual beds. If I want to plant at 9”, I plant into every other hole, staggering them to give them maximum space. It does mean I get weeds in all the ‘empty’ holes, but that isn’t too much of a problem compared with having to change the sheet of membrane.

9” (21cm) spacing in a linear pattern, with self sown Agrostemma and a few weeds. Cat for scale!

9” (21cm) spacing in a linear pattern, with self sown Agrostemma and a few weeds. Cat for scale!

Foxgloves planted in alternate holes, staggered pattern into membrane with 6” (15cm) spaced holes. Weeds in the empty holes!

Foxgloves planted in alternate holes, staggered pattern into membrane with 6” (15cm) spaced holes. Weeds in the empty holes!


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Is all this planning needed?

Do I really need to do all this? 

Well, if you want to grow efficiently, grow the right crops, in the right quantities, not waste your time and energy growing flowers which you won’t sell, then yes, you do. In time, you will learn how much you generally need, and you may not need to calculate it each year ( I know the numbers now, so I just use the beds as a planning tool) but it’s important to get to grips with this process first. It’s like learning any skill, it’s clunky and awkward to begin with, and you need to go through the motions, follow the recipe step by step…until you're confident and can adjust it as you go, and make improvements. 

However, there are a few possible exceptions…

  1. If you grow only long-standing perennials with a long season e.g. foliage (although you will still need to get the quantities and mix right for your customer base)

  2. If you grow only one crop (although you still need to know your quantities and any colour variations)

  3. If you are primarily a florist, sourcing lots of your material elsewhere and just growing elements that you can use to add interest and value (but you still don't want to be growing things you don't use, or wasting seed or plants).

You also need to build in development for the future, do you want to be able to take on additional markets next year, will your planning need to cover that possibility or not?

You learn by planning, experimenting, doing it, and then reviewing it afterwards, and then planning all over again!

Claire planning on the field.jpg