Propagation: growing from seeds, cuttings and division
Fill your garden with amazing edible and useful plants for low or no cost! Learn all the secrets of propagating plants from seed, cuttings and division.
Propagation from seeds
Why grow from seed?
Seeds contain the beginning of a new plant
Growing from seed is an economical way to produce new plants
Many rare vegetables, herbs and fruit are only able to be sourced as seeds
Facts about growing from seed
Plants grown from seed will always differ from the parent in some way – some may be very similar, others very different
Seeds usually need light and moisture to grow
Check a reliable planting guide as to whether it is the right time of year to plant that type of seed - some seeds need warmth to germinate eg tomatoes, basil, others need cold to germinate so don’t try these in summer, such as Asparagus
Seeds have a ‘Use By’ date - check before buying or sowing
Most seeds germinate between 7 and 21 days after sowing, but some may germinate in 2-3 days or take much longer
Growing from seed
Seeds should be grown in seedling mix, or in very fine soil in the ground - seedlings may have trouble emerging past large soil particles
Seeds should be sown at a depth approximately twice their size
Sterile pots and equipment are really helpful
Always water soil before sowing seed and lightly water after
Fine seed can be sprinkled across the soil surface and a sieve used to sprinkle fine particles over the seed
Keep seeds moist while germinating and growing to avoid seed death
Use a spray bottle to mist small seeds to keep moist – from once to several times per day depending upon weather
A mini watering bottle can be made by piercing the top of a plastic water bottle with a metal skewer heated over a flame
Label seed and seedlings when planting with name of plant and date planted for later reference
Direct sowing of seeds
Sowing direct is sowing seed directly into the garden where they are to grow
Larger seeds (peas, beans, zucchini, pumpkin) prefer being sown direct
Root vegetables (carrots, beetroot) don’t like being moved so should be sown direct
Many larger seeds can be helped by soaking for a few hours or overnight in warm water or a weak seaweed solution
Indirect sowing of seeds
Indirect sowing of seeds can include sowing into seedling punnets or tubes
Seeds are planted into seedling mix
When seedlings have grown two sets of leaves they need to be transplanted into potting mix or into the ground – the second set of leaves are the first ‘true’ leaves
Seedlings can be grown on in small tubes or pots to allow them to become larger before planting out into the garden – this is useful for plants such as tomatoes
Take care not to damage the delicate roots of the new seedlings when transplanting – don’t allow the roots to become squashed in any way and trim long roots if needed
Firm the potting mix gently around the seedling and water in gently with diluted seaweed solution
Seed sowing in biodegradable pots
Biodegradable pots give the advantages of direct and indirect sowing
Seeds are planted into seed growing mix in paper pots (recycled toilet rolls, envelopes) or pots made from coir peat, and once seedlings are planted out when ready
Seeds planted in biodegradable pots can be started in warm conditions inside your house then planted outside to allow an earlier planting time for a crop such as climbing beans
Protecting seeds and seedlings
Seeds and seedlings need to be protected from a variety of pests, including snails, slugs and earwigs
Protection from birds can be given by re-purposing old hanging baskets
For snails and slugs use old coffee grounds around seedlings, or crushed egg shells
Beer in jars set into the garden at ground level attract snails to a pleasant death
Upside down grapefruit halves (after squeezing out juice) attract slugs overnight
Earwigs like to hide in crushed newspaper drizzled with oil from canned tuna, stuffed into upside down plastic pots – shake earwigs into a bucket of water in the morning to drown them
Seedlings can be protected with guards made from old plastic drink bottles
If you need snail bait, use only red-coloured snail bait, which breaks down to iron in the garden – all green snail bait is still poisonous even if not attractive to animals or birds
Pre-sprouting of seeds
Seeds can be helped along by pre-sprouting – also speeding up the time to produce seedlings
Seeds are placed between damp paper towelling sealed inside clear plastic containers
Use wetter paper towelling to help wet larger seeds
Use only damp paper towelling for smaller seeds
Place containers (recycled take-away food containers) on warm, light window sills
Check each day to make sure paper is kept moist
Seeds can be planted into the ground after sprouting
Propagation by Cuttings
What are cutting and why take them?
Cuttings are a piece of a plant that is used to grow a new plant
Cuttings are an economical way to produce new plants
Cuttings allow us to produce a true copy of the original plant, ie a clone
Cuttings work because the nodes of a plant are able to produce roots or leaves from them, depending upon whether they are above or below the soil
Basic rules of taking cuttings
Always take cutting from healthy, vigorously growing plants
Avoid taking cuttings from plants at a time that they are flowering or have flower buds • Sharpen secateurs before taking cuttings to ensure a clean cut – a ragged cut may lead to infection in the cutting and it may fail.
Sterilize secateurs before taking cuttings – this can be done easily with a spray of methylated spirits
Cuttings should always be taken node to node
Aim for 1-2 nodes below the propagation mix and at least 1-2 nodes above the mix, to give more chances of root and shoot growth
Length of a cutting depends on the distance between the nodes – so a greater distance between nodes means longer cuttings overall
General information for growing cuttings
When propagating at home, a 50% success rate is good – some plants such as Feijoas are difficult to grow from cuttings and all may fail, however with Rosemary cuttings more than 50% usually grow
Cuttings are best grown in propagating mix, which allows even moisture retention while ensuring good drainage to prevent rot
Keep an eye on cuttings and if any turn brown remove them immediately so as not to infect other cuttings in the same pot
Plant cuttings by making a hole in the propagation mix and inserting cutting - this avoids damaging the base of the cutting as you push it into the propagation mix
Firm around each cutting and water in well
Keep propagation mix around cuttings moist at all times
Cuttings can be planted individually into tubes, or several planted into larger pots or foam fruit boxes
Many cuttings benefit from bottom heat to encourage the roots to grow, which can be supplied by a specialized propagating box with inbuilt heater, or by sitting a tray of cuttings on top of an open compost heap with lots of lawn clippings
Cuttings can be helped by dipping the ends into Manuka honey – this helps to stop infections in the cutting that could cause it to fail
Cuttings can also be helped by dipping into willow branch tea - made from soaking new willow branches (not leaves) in water for a few days (or by making ‘tea’ with boiling water and leaving overnight to steep). Willow tea contains salicylic acid, which helps prevent infection in the cuttings you are dipping into it.
Tip and semi-hardwood cuttings are usually ready to be potted up not long after they start to show new growth – usually indicating that they are growing roots, or if there are roots emerging from the bottom of the tubes or pots they are in.
Hardwood cuttings may show leaf growth before they have root growth – check for root tips appearing at the base of the pots before re-potting
Types of cuttings
Tip cuttings
Take in spring
Tip cuttings grow fairly quickly
Cut actively growing plant tips
Take cuttings approximately 50mm long from the very tip of the plant where the stem is soft and green –
Remove leaves from the area below the mix and plant immediately
Most tip cuttings need to have their leaves kept humid, to avoid drying out, either with a specialized propagating box with lid, or re-purposed jars or soft drink bottles acting as a min-glasshouse.
Small, light, clear plastic bags can be used as mini greenhouses too, making sure to keep the bag from touching foliage by means of skewers.
Some cuttings may not thrive with a mini-greenhouse, such as more Mediterranean plants eg Rosemary, Lavender. These plants may develop fungal problems if placed in a mini-greenhouse as they prefer non-humid conditions.
Types of plants that work well from tip cuttings – Salvias, Mints, Correas, Westringias, Lavenders
Semi-hardwood cuttings
Take in autumn
Semi-hardwood cuttings take longer to grow than tip cuttings
Take cuttings a bit further along the stem than the tip, where the stem is tending from green towards brown.
Take cutting approximately 70-120mm long
Remove soft tip growth and lower leaves and plant immediately
Broad leaves remaining can be cut in half to avoid the cutting lose too much moisture
May benefit from a mini-greenhouse (if plant type is appropriate)
Sometimes semi-hardwood cuttings can be grown in a glass of water on a sunny windowsill eg Pineapple Sage– experiment with different types of plants and varying times of the year
Types of plants that can be grown from semi-hardwood cuttings – Pineapple Sage, Lemon Verbena, Feijoa, Camellia
Hardwood cuttings
Take in winter
Hardwood cuttings take longer to grow than semi-hardwood cuttings – sometimes months or even a year!
Take from older wood, at least as thick as a pencil if possible (some plants may not have wood this thick)
Approximately 150-200mm long
Making sure to plant cutting the right way up!
To help with this, cut bottom of cuttings straight across, and tops of cuttings at an angle
If any leaves remain, remove these when you take the cutting
Types of plants that work well from hardwood cuttings – Grapes, Gooseberries, Currants
Potting up your cuttings
Tip cuttings or pots of cuttings out gently onto a sheet of newspaper or a clean potting bench
Gently untangle roots from adjoining plants if necessary
Trim any long roots that will end up coiled in the bottom of your new pot as these may be squashed and die off
Place cutting into a slightly larger pot than before and tip potting mix around the roots while you hold the cutting at the correct height, to avoid squashing the roots
Firm the mix gently around the roots and water in well with a weak solution of seaweed fertilizer or worm tea
Newly potted up cuttings need to ‘harden off’ for a few days in a sheltered spot before being introduced into full sun once again
After the cutting has filled out the new pot, it can be planted directly into the garden or into a larger pot
Propagation by Division
Why grow by division?
Many plants benefit by lifting and dividing every couple of years
Growing by division is an economical way to produce new plants
Growing by division allows you to share plants with others easily
Facts about growing by division
Plants grown by division will always be the same as the parent plant
Plants suitable to grow by division are those that spread roots as they grow such as Oregano
Many strappy foliaged plants are suitable for propagation by division, such as Society Garlic and Daylilies
Plants unsuitable to grow by division are those that have a central woody root system such as Lemon Thyme
How to divide plants
Take plant out of pot or dig plant up and put plant onto a sheet of newspaper
Gently tease roots apart –trim roots with secateurs rather than pulling if needed
Trim off about half of the foliage so as to give the new plants a chance to recover
When potting up the new plants be careful not to have roots squashed in the pot – hold the plant at the right level in the pot and fill with potting mix around roots