The Ultimate Guide to Plant Propagation: Domes, Lights, Nutrients & Cuttings

Taking cuttings is a practical way to grow more plants from a healthy donor plant. For plants suited to this method, it helps you preserve the characteristics you value and build a consistent supply of young plants for your garden.

Fresh cuttings need careful handling because they have not yet developed roots. A clean growing medium, gentle light, suitable warmth and controlled humidity help them stay hydrated while roots form.

This guide focuses on soft-stem cuttings. Requirements vary by plant species, so use the guidance as a starting point and adjust it to the plants you are growing.

Choosing a propagator

A propagator helps maintain humidity around cuttings and protects them from sudden changes in their environment. Choose a dome with adjustable vents and enough space to keep foliage clear of the cover. Monitor conditions rather than relying on condensation alone.

Stewart propagators

Stewart offers straightforward propagator options for home growing setups.

• Unheated propagators: Suitable when the surrounding room or greenhouse already provides enough warmth. Adjustable vents help you manage humidity as cuttings establish.
• Heated propagators: Useful in cooler locations where additional root-zone warmth is needed. Check the model's temperature controls and monitor the growing medium to avoid overheating.

AC Infinity humidity domes

AC Infinity dome setups offer options for integrated lighting and adjustable ventilation. Depending on the model, height extensions can provide extra clearance for taller cuttings. Check what is included and which lights or controllers are compatible before choosing a kit.

Seedling heat mats

A heat mat can help maintain a suitable root-zone temperature in a cool growing space. For many soft-stem cuttings, approximately 21–25°C is a useful starting range, but the ideal temperature depends on the species.

Use temperature control where available and position the probe according to the manufacturer's instructions. Check that starter plugs remain moist and that the medium does not become too warm. Follow the product's electrical and water-safety guidance.

Propagation lighting: start gently

Fresh cuttings need light, but strong light can increase water loss before roots are able to replace it. Start with gentle, evenly distributed lighting and watch for wilting, bleaching or excessive stretching.

• Intensity: The original starting range of 30–80 µmol/m²/s can be used as a cautious trial for suitable soft-stem cuttings, not a universal target. Increase light gradually once roots establish.
• Schedule: Use a consistent light-and-dark cycle suited to the species. An 18-hour light period is used in some indoor propagation setups, but is not necessary for every plant.
• Spectrum: White propagation lights make it easy to inspect foliage and provide a practical option for young plants.

LED bars and T5 lighting

Low-wattage LED bars, including suitable AC Infinity IONBEAM models, can provide compact propagation lighting. T5 fluorescent fixtures are another option, although they add more heat to the growing area. Follow the fixture's recommended mounting distance and adjust it to the plants' response.

Growing media and gentle feeding

Use a clean, airy propagation medium that holds moisture without becoming waterlogged. Strong nutrient solutions can stress fresh cuttings and damage emerging roots, so avoid treating them like established plants.

Rooting gels, young-plant feeds and root-support products have different purposes. Use only products suitable for your medium and plant species, and follow their current label instructions rather than combining them at full strength.

Brand	Products to consider	Role in the setup
Plagron	Seeding & Cutting Soil NextGen Rooting Gel	Propagation medium and rooting gel
Biobizz	Light-Mix Root·Juice	Lightly fertilised growing medium and root-support product
CANNA	CANNA Start RHIZOTONIC	Young-plant feed and root-support product

Plagron

Plagron Seeding & Cutting Soil is an option for starting young plants. NextGen Rooting Gel can be used when preparing suitable cuttings. Follow the instructions for your chosen product and avoid contaminating the original container.

Biobizz

Biobizz Light-Mix offers a lightly fertilised medium for young plants. Root·Juice is a root-support option to consider alongside a suitable growing medium. Check the recommended application stage and dilution before use.

CANNA

CANNA Start is formulated for young plants, while RHIZOTONIC is a root-support product. Choose an application method and dilution specified on the label. Do not assume that a root-treatment dose is also suitable for spraying foliage.

How to take soft-stem cuttings

What you will need

• A healthy donor plant suitable for propagation by cuttings
• Clean, sharp secateurs, scissors or a suitable cutting blade
• A suitable tool disinfectant, used according to its instructions
• Starter plugs or a clean propagation medium
• A tray and ventilated propagator dome
• A rooting gel, if appropriate for the species
• Gentle propagation lighting
• A temperature-controlled heat mat, if additional warmth is needed
• Plant labels

1. Prepare the growing medium

Have the tray, medium and dome ready before taking cuttings. Prepare plugs according to their manufacturer's instructions, including any medium-specific pH guidance. Allow excess water to drain; do not squeeze rockwool plugs, as this can damage their structure.

The medium should be evenly moist, not sitting in stagnant water. Set up the lighting and any heating equipment, then check conditions before adding plants.

2. Choose a healthy shoot

For many soft-stem plants, a shoot around 10–15 cm long with two or three nodes is a useful starting point. Avoid damaged, diseased or overly weak growth. Take only as much material as you can prepare promptly.

3. Make a clean cut

Use a clean, sharp tool to cut just below a node where appropriate for the species. An angled cut is commonly used, but a clean cut and suitable placement matter more than achieving an exact angle. Avoid crushing the stem, and do not scrape it unless the species-specific propagation method calls for it.

4. Prepare the foliage

Remove leaves that would sit below the surface of the growing medium. Retain enough healthy foliage to support the cutting. For large-leaved species, reducing some leaf area may help limit water loss and crowding; it is not necessary for every cutting.

5. Apply gel and insert the cutting

If using rooting gel, pour a small amount into a separate clean container and follow the label instructions. Do not return unused gel to the original container.

Make a planting hole, insert the stem gently and ensure the medium supports it without crushing it. Keep leaves above the surface and label the cutting.

6. Set up the propagator

Place the cuttings under gentle lighting and fit the dome if the species benefits from raised humidity. Keep foliage clear of the cover. Adjust vents to maintain hydration while allowing air exchange, and monitor both the air and root-zone temperatures.

Daily care and hardening off

Rooting time varies considerably by species, season and growing conditions. Treat the following stages as a guide rather than a fixed 14-day deadline.

Early days: maintain hydration

Check cuttings daily for wilting, excess moisture and signs of decay. Keep the medium moist but not saturated. If humidity needs increasing, lightly mist the dome walls rather than repeatedly soaking the foliage. Avoid leaving the propagator in direct sun, where temperatures can rise quickly.

While roots develop: balance moisture and airflow

Adjust ventilation gradually as cuttings remain upright and stable. Water only when the medium needs it, allowing excess water to drain. Avoid pulling cuttings out to check their progress, as this can damage new roots.

Once roots appear: acclimatise gradually

When roots are visible and the plants are growing, increase ventilation and begin short periods without the dome. Extend these periods gradually. If the plants wilt, slow the transition and check moisture, temperature and light intensity.

Potting on

Transplant once the cutting has enough roots to hold its medium together. Use a suitable potting mix and handle the root system gently. Increase light and feeding gradually according to the species and the nutrients already present in the medium.

Troubleshooting

Wilting cuttings

Check: Excessive light, high temperatures, low humidity or dry medium.

Action: Reduce light intensity if needed, bring temperatures back into a suitable range and check moisture. Adjust dome ventilation without creating a hot, stagnant environment.

Soft or rotting stems

Check: Waterlogged medium, poor airflow or contaminated equipment.

Action: Remove affected cuttings, drain standing water and improve ventilation. Clean the tray and tools before taking replacement cuttings.

Yellowing leaves

Check: Root development, light intensity, moisture and the plant's feeding requirements.

Action: Correct the growing conditions first. Avoid adding strong feed or foliar sprays without checking that they are appropriate for the plant and product.

A reliable propagation routine

Successful propagation starts with healthy donor plants, clean equipment and a suitable medium. Keep light gentle, monitor warmth and moisture, and give each cutting time to establish roots. Gradually acclimatise rooted plants before potting on, and record what works for each species so the next batch is easier to manage.