A suggested maximum light intensity is between 100 to 150 µmol∙m−2∙s−1 from the time cuttings are stuck until the initial roots form (a few millimeters in length), which is usually the first five to seven days of propagation. A retractable screen is best so that it can be opened during cloudy conditions.
We recommend a photoperiod of 12-13 hours for the propagation of most annuals, especially for long-day plants such as petunia. Light Intensity. Desirable levels of light vary, depending primarily on the stage of root development.
Cuttings use energy to form new roots. If the cutting has leaves, most of the energy comes from photosynthesis. Expose these cuttings to bright light, but not direct sunlight, during the rooting period. If you use hardwood cuttings that have no leaves, the energy will come from reserves stored in the woody stem.
The cuttings require sunlight in order to root. Put them in a bright spot, but not in direct sunlight, or they will dry up and wilt. Various factors, including the plant species and soil temperature, will affect how long it takes for roots to form on the cuttings. The ideal temperature is 25 to 27°C.
The best light cycle for rooting cuttings is generally 18 hours of light and 6 hours of darkness. Do not supply cuttings with 24 hours of light without any dark periods because this has shown to slow the rooting process down as plants root best with a sufficient dark period each day.
Warm growing medium temperatures accelerate cell division which leads to faster callusing, root initial development and subsequent root growth. It also speeds up the dry-down rate of the growing medium, which also helps encourage better rooting. The best way to warm the growing medium is through bottom heat.
Unlike seedlings, humidity needs to be much higher for cuttings. That's why you'll need a humidity dome over your clones to make sure they get enough moisture for their roots. Keep the dome on and make visual checks every day for signs of mold or mildew on your clones.
Media is usually kept at 72-77° F while air temperature is maintained at 68-73° F. If bottom heat is not used, air temperature should be maintained between 77 and 80° F. Maintaining air temperatures lower than medium temperatures retards shoot growth while promoting root development. Excessive heat can damage cuttings.
Controversially, I'm gonna suggest you don't water them very often. I would start with very evenly moist airy soil – water in sans cutting, and mix it round so it's not saturated at the bottom. Add your cutting, and then mist the surface thoroughly daily (trying not to get the cutting). Twice a day if it's hot or dry.
It will slow transpiration while the necessary components are used at the root sites to build a new root structure. Keep the atmosphere around the cutting warm (not hot), keep the humidity relatively high (>90%), and keep the root zone temperature warm (at about 25°C).
The sooner you can get your cuttings into a more normal environment with air flow and no dome, the better off they'll be. After about a week, remove the dome and monitor your cuttings to see if they begin to wilt. If they do, they're not ready to go dome-less, so try again in 1-2 days.
A typical misting frequency during sticking (Stage 1) and callusing (Stage 2) of vegetative cutting propagation is to initially mist for 5–8 seconds every 5–10 minutes over 24-hour period. After three to four days, reduce mist to 3–5 seconds every 10–20 minutes during the day, and less frequently at night.
Time it right
It's an easy and satisfying way to increase your stock of plants. It's always best to take cuttings early in the morning, when the parent plant is still turgid, i.e. full of water.
Plant patents
Translation: you cannot divide that overgrown perennial, root cuttings, or layer branches if the plant is protected by a plant patent. Basically, the only legal way to reproduce a plant with this type of patent is by seed.
Some plants will root in water, but cuttings will develop a better root system when rooted in a soil-less potting mix. Sand or perlite can also be used, especially for cuttings that need good drainage and may rot if kept too wet.
It is a violation of a plant patent if you propagate the plant in any asexual way. That includes rooting cuttings from a patented plant, but it also includes planting the “daughters” of a patented strawberry mother plant in your garden. Seeds can also be protected by patents.
That's why many growers choose Philips as the best LED propagation light. Faster and stronger rooting, more uniform, compact plants and higher propagation success rates. With Philips LED plant grow lights, flowers, perennials and potted plants get the right start so you can deliver the very best across the board.
Spectrum for Photosynthesis, Growth, and Yield
For growth, blue light is essential to help plants produce healthy stems, increased density, and established roots – all which occur in the early vegetative growth stages.
Metal halide bulbs are the most popular propagation lights as they produce blue spectrum light that promotes the growth of green foliage.
Several cuttings may be placed together in one container. Be sure to add fresh water as needed until the cuttings are fully rooted. Rooting will generally occur in 3-4 weeks but some plants will take longer. When the roots are 1-2 inches long or longer the cutting is ready to be potted up.
Technically, you can transfer your cuttings to soil at any time. In fact, you can actually propagate directly into soil, however, it's much harder to do within your home. When you propagate in soil, you have to keep a good balance of soil moisture, air flow, and humidity.