Should we allow the cuts to dry out a little before sticking them in medium? No - while herbaceous cuttings are less likely to rot, they also root faster than woody plants because they contain less lignin in their stems. Don't give them time to dry out.
Just Add Water
Bottled spring water or well water works best, due to the higher levels of minerals. Put your cutting in a clear glass jar or vase so the roots can get some sun. Use a beaker or bottle-shaped vase so the cutting stays nicely in place. That's it!
And they tend to rot if you don't wait for the cutting to form a callus, a hard, dry “crust” at the base of the cutting. That can take anywhere from a few hours to a few weeks, even a few months in extreme cases. In general, the thicker the stem, the longer it takes to seal itself off.
However, if you struggle with your cuttings rotting, then you might want to try letting your cuttings callus over for a couple of hours (or overnight) before putting them in water.
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.
Providing too much moisture during propagation can result in rot and cutting loss. A practice often observed during propagation of unrooted cuttings is frequent, heavy misting, which provides too much moisture and should be avoided.
The reason cuttings rot is that over time, the oxygen level of the water drops unless it's moving or oxygen is added. Not only do plants need oxygen in order to grow roots (and, indeed everything else), but the bacteria that cause rotting thrive in low-oxygen environments.
(Many plants will root successfully from cuttings without the use of rooting hormone, but using hormone can speed up the process, and it might be essential for some hard-to-propagate plants.) If you are using a powdered hormone, it helps to moisten the stem before rolling it in the powder.
Use rooting powders.
You can increase your chances of success by using rooting products, Clark said. Many commercial products are available. These products kill fungus and bacteria to prevent the stem from rotting, and contain a growth hormone to speed the formation of roots.
The problem is if the cutting is too long the plant is more likely to wilt and stress. If the cutting is wilting it's far more likely to fail and not generate roots. Smaller cuttings will lead to better success rates and overall better outcomes for you and your cuttings.
Most indoor and some outdoor plant species can be propagated in water. The rule is simple - trees, shrubs, and herbaceous plants that grow in humid areas or reproduce vegetatively (for example, Aroids) can be propagated in a humid environment, i.e., water. Such plants as succulents can be rooted in water too.
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.
Carefully remove excess leaves to reduce transpiration, so cuttings do not wilt. However, some foliage should be retained to allow photosynthesis to occur. Keep cuttings moist, cool and shaded (collecting in a damp plastic bag is a good idea) until you are ready to put them in a propagation medium.
Place the cutting in a clean glass. Poor enough room temperature water to cover the nodes of the cutting. Change out the water every 3-5 days with fresh room temperature water. Wait and watch as your roots grow!
It's important that your water propagated plants receive some light, but bright indirect light with no direct sun is important. They are growing new root systems and are fragile.
Ideally, the temperature of the medium should be maintained slightly higher (5°F-8°F) than the air so that callus and root growth occur faster than shoot growth. To accomplish this, bottom heat- ing is required. Desirable propaga- tion temperatures are 73°F-77°F for the medium and 68°F-73°F for the air.
The two main nutrients that support excellent root growth in plants are phosphorous and potassium. These two ingredients are extremely helpful in any fertilizer mix that needs to encourage a thick, healthy collection of brand-new roots, or to strengthen and stimulate existing systems.
Roots are dynamic and their growth is strongly affected by the environmental conditions found in the root zone. To survive and grow, they need Air (gas exchange), Water, Non-limiting Temperature, Carbohydrates, Minerals, Space, Low Soil Density, Microbial Associations and Non-toxic soil chemistry.
Cuttings will root more quickly and reliably in warm rooting mix. Keep your cuttings between 65°F and 75°F, avoiding excessive heat. If your area is too cold, consider a heating mat or cable especially designed for this purpose.
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.
Auxins stimulate root formation on the stem cuttings, e.g., IBA, IBA-alanine, NAA. NAA is synthetic auxin while IBA is considered as both natural and synthetic.
Hydrogen peroxide can help to control fungal growth and fungal infection, such as root rot, by preventing the growth of fungi. It can also help kill fungus and bacteria on plant roots.