Propagation: growing from seeds, 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