Propagation




Taking Stem Cuttings - 20 Indispensable Tips!

Many beginners are put off taking cuttings by the many guides out there that make it sound like advanced brain surgery. Here we blow the lid off this very easy process starting with 20 great tips to get you on well along your way to success!

1. Temperature

Try to keep the propagator temperature above 64°F (18°C,) but don't let it exceed 75°F (24C°).

2. Humidity

Keep the vents on your propagator closed to keep the humidity above 90%. Once the cuttings have produced roots open the vents to lower humidity and encourage transpiration.

3. Water

Over saturated growing media has to be the number one cause of cutting failure. After pre-soaking your propagation plugs you should rarely have to re-water them before roots appear if conditions are right.

Lavender cutting beginning to show roots in a Rapid Rooter propagation cube by General Hydroponics (Lavandula Dentata)

4. Nutrients

Use a cutting specific nutrient to help with fast rooting and optimum nutrition. Don't overdo it as a high EC can inhibit root initiation. Remember to adjust pH according to your chosen rooting media.

5. Light

Cuttings don't need intense light to root. Using fluorescent T5 lamps above propagator is highly recommended.

6. Cycle

Where possible try to match the cuttings' light cycle to the same as donor plants. This will minimize shock and help to ensure quick establishment.

7. Patience

Most soft wood cuttings usually take around 10-14 days to root in a regular propagator.

8. Donor plant

Your cuttings will only be as healthy as the stock or "mother" plant you took them from. Obviously, you should avoid takings cuttings from a diseased, stressed, flowering, or overfed plant.

9. Plant hole

Don't allow the cutting to flop around loosely in the plug's planting hole. Ensure the cutting is firmly inserted and stable. Make your own off-center planting hole if the existing one is too big.

10. Heated Propagators

Bottom heat can help encourage good root formation, especially when propagating tropical plants, but keep an eye on your thermometer as heated propagators without a thermostat can raise temperatures too high. Using a timer or thermostat can help in this situation. Also continuously monitor moisture levels in the rooting medium when using bottom heat and replenish as necessary. Letting your rooting medium go completely dry during a propagation cycle will result in failure.

11. Size

Don't take big cuttings with large stems, go for smaller cuttings around 2-4 inches in length and trim off unnecessary leaf material.

12. Rockwool

Don't squeeze rockwool plugs or blocks to remove excess water! Doing so breaks down their structure and could damage developing roots. A better way to expel excess water is to give them a vigorous flick or shake.

13. Rooting Hormone

Use a good quality rooting compound but remember to check its "use by" date as they don't tend to have a long shelf life. Don't use too much, just dip the tip or follow the manufacturer's recommendations.

14. Destiny

Avoid using rockwool for cuttings if your plants are destined for soil. Wherever possible match the cuttings growing media with its final use as this will minimize transplant shock.

15. Beneficials

Use beneficial bacteria and fungi in your pre soak solution at a high dose. Root zone colonization at an early stage will ensure healthy, disease resistant roots that grow fast and support a vigorous plant.

16. Additives

Some root stimulators that contain seaweed extract should not be used until roots have emerged. Always check that what you're adding to your pre-soak solution is suitable for cuttings.

17. Propagator Tray

Never let your cuttings stand in tray with water in the bottom. Using a bed of perlite or pebbles can help create a reservoir of moisture without the risk or over-saturating your propagation cubes.

18. Hardening Off

Once your cuttings have produced roots, slowly adjust them to their new growing environment by slowly opening humidity control vents for a short period every day, building up to leaving the propagator lid ajar or askew on the propagation tray, to finally removing it completely.

19. Air Pruning

If you plan to transplant into larger rockwool blocks try putting the blocks on wire mesh or rack to allow air to pass underneath. Once the primary root tips grow through the block they will be exposed to drier air under the block, stop growing and die back. This stimulates an abundance of secondary roots to branch out throughout the block until they get air pruned and then stimulate more root growth. The overall effect of this growth and pruning cycle will create a plant with a well developed root system throughout the entire block. Air pruning can also be done using various types of potting media using Air-Pots or fabric Smart Pots.

20. Breaking In

Once you have created healthy cuttings in your propagation area, break them into your grow room gently. When using high wattage HID lights, keep them raised up high initially. If you're using multiple lights you may not need them all on.  Try to keep the humidity high and temperatures moderate to give your new plants the best start possible!