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DeutschSowing your own rootstocks means producing your plants from start to finish and, above all, knowing the quality of their roots. Here is how I choose the seed, the container and the growing medium, then how I sow, with photos from the nursery.
At a glance
- Who it is for : home growers who want to produce their own rootstocks, from seed to a plant ready to graft.
- When : January to April depending on region and weather; I sow from mid-January, under glass.
- Container : as deep as possible: a cell tray or a 7x7x18 pot.
- Growing medium : a professional, fine-grade compost.
- Germination : it can take several months; here, the first seedlings appear in March.
- Then : a year of growing, followed by selection of the plants.
On this page : Why sow · Which rootstock · Stem and roots · The seed · Sowing step by step · After sowing · Common mistakes
Why sow your own rootstocks?
That is the first question to ask! Starting from seed and producing your plants from start to finish is very satisfying, but for me the main benefit is the quality of the plants. When you buy a rootstock or a grafted plant, you do not know the state of its roots. Most of the time there is no problem (depending on how rigorous the grower is), but I look at the root system of every plant of mine that dies, and I often find a root problem.
The second benefit is financial, if you want to produce a fair number of rootstocks. Even so, once you add up the cost of seed, cell trays, compost, water, fertiliser, time, selection and so on, I am not sure you can compete with Spanish growers, especially for just a few plants.
Which rootstock to choose?
The choice of variety depends on your soil and your climate. The characteristics of the main rootstocks used in our latitudes are given on the certified seed page and in the tutorial how to choose a rootstock:
- Citrange C35;
- Citrumelo 4475;
- Poncirus trifoliata;
- Volkameriana.
Forner Alcaide 5 (Fa5) is not sold as seed: it is a protected plant variety.
No perfect rootstock
Choosing a rootstock is a compromise between hardiness, suitability for your soil, disease resistance and compatibility with the variety you want to graft. Sadly, there is no universal, perfect rootstock!
Either way, you want two things from a rootstock: a nice straight stem, for looks (to taste!), and a good root system, suited to your soil.
A straight stem and good roots
For a straight stem, all you need is fairly level ground, fairly dense sowing or a cane. Cell trays give an unrivalled density of plants: the rootstocks guide one another.
For the roots, two factors matter: the depth of the container and the growing medium.
1A deep container
A cell tray lets you raise a lot of plants per m²; on the other hand, the compost dries out faster than in a pot holding twice as much.
In pots or trays, you need a container as deep as possible to protect the taproot.
The taproot needs depth.
The taproot comes first
When the seedling is only just showing, the taproot is already 4 to 5 cm long.
A seedling just out, with 4 to 5 cm of root already.
Did you know?
Have you ever noticed that self-sown cherry seedlings, for example, need no watering? Unlike the cherry trees you buy, which have to be watered every fortnight for the first 2 or 3 years…
2A good growing medium
After several years of trials, I have seen a big difference between cheap composts (to be avoided, obviously!), mid-range ones and professional ones. The quality and fineness of the compost limit gooseneck roots.
My best results so far have been with Klasmann Potgrond H.
Our 2023-2024 trial: Potgrond H (Klasmann) gave the best results, ahead of Traysubstrat and Jiffy pellets.
Getting seed
Once the variety is chosen, you need good-quality seed: either certified seed or seed collected from rootstock fruit.
ACertified seed
Keep it in the fridge, for as short a time as possible before sowing.
BSeed collected from a rootstock
Leave the seed in the fruit until the last moment. The fruit can be stored heeled in, in sand.
Take care not to sow too late, or the seeds will germinate inside the fruit (from mid-January here for Poncirus, for instance).
The seeds stay in the fruit until the last moment.
CUncertified seed
Be rigorous with selection, to weed out off-type plants caused by possible hybridisation: see growing your own rootstocks.
When to sow? The ideal time is January to April, depending on region and weather. I sow from mid-January, under glass.
Sowing step by step
1Choose the container
As we have seen, the container should be as deep as possible. By my criteria, the best compromise is a cell tray or a 7x7x18 pot.
2Fill and firm
Fill the trays and firm the compost in 3 passes, especially at the edges, which are always less compacted.
Three passes to firm it well, edges included.
3Make the holes
Make the holes by hand or by pressing another tray into the compost.
The holes are made.
4Place the seeds
Drop the seeds into the small holes.
One seed per hole.
5Cover, firm and label
Add more compost and firm it well so that the seed does not move when watered. Add an identification label: a number or the name.
The finished, labelled tray.
6Water
A good watering and you are done!
Careful when moving trays
Once filled, a tray must be carried across its width, as in the photo for step 5: otherwise it bends or breaks in the middle!
After sowing
During germination
It can take several months, depending on the weather. Check that the compost stays moist and watch out for rodents, which dig up the seeds to eat them, as well as snails and slugs, which love to hide under the trays.
A tray to keep an eye on during germination.
The first seedlings
I sow under glass on a hotbed from mid-January: the first seedlings appear in March.
The first ones are up.
In under a fortnight
After that, things move fast.
Less than a fortnight later.
The first year
Water well and mist the trays.
After a year of growing
The plants have grown well: time for selection, covered in the tutorial growing your own rootstocks.
After a year of growing.
Common mistakes and how to avoid them
A container that is too shallow
The taproot is already 4 to 5 cm long when the seedling emerges: use the deepest container you can (cell tray or 7x7x18 pot).
Cheap compost
Use a professional, fine-grade compost: it limits gooseneck roots.
Certified seed kept too long
Keep it in the fridge and sow it as soon as possible.
Sowing collected seed too late
It may germinate inside the fruit: from mid-January here for Poncirus.
Poorly firmed tray edges
Firm in three passes, paying attention to the edges.
A seed that moves when watered
Cover and firm well before watering.
Carrying a tray by its length
Carry it across its width, or it will bend or break.
Forgetting about pests
Watch for rodents, snails and slugs during germination.
For sowing and going further
- Certified rootstock seed : Citrange C35, Citrumelo 4475, Poncirus trifoliata…
- Plant-in identification labels for rootstocks
- Growing your own rootstocks : selecting the plants, from emergence to a plant ready to graft.
- How to choose a rootstock : to pick the right rootstock for your area.
- Rootstocks : for those who would rather save time.
Other tutorials: cleft grafting · bark grafting · whip-and-tongue grafting · chip budding
Ready to sow?
Certified rootstock seed and labels are in the shop. A question about your seedlings? Get in touch.