While fertilizer isn't necessary in the early stages, adding it later can boost growth for long-term water propagation. Using a highly diluted solution ensures that the new roots get the nutrients they need without the risk of over-fertilization.
Fertilizer, yes. I would theoretically recommend waiting to add fertilizer until there's root growth to prevent the cutting from being overrun with algae, but in practice I add it at the beginning and it's never done me wrong.
There are lots of fertilisers suitable for water propagation. My favourite is called GT CCS, made by the same company who make Clonex. You can get CCS from Amazon also. It's a complete root fertiliser, gentle enough for cuttings and seedlings, and also formulated for use in water, not just in soil.
This allows plants to continue to receive a constant supply of nutrients and prevents nutritional deficiencies. Another strategy is to drench cuttings with a fertilizer (200-300 ppm) once roots have developed (for example, 10 days after sticking cuttings for many crops).
Success factors for rooting your cuttings
They'll root faster with plenty of sunlight, but avoid setting them in direct sun. Temperature is also important, the warmer the better to speed things up. For cuttings that are more valuable or difficult, adding a little aquarium pump to oxygenate the water will help a lot.
Inadequate Moisture: Cuttings need to be kept moist, but not waterlogged. Overwatering can lead to rot, while under-watering can cause the cutting to dry out and die. Use a spray bottle to mist the cuttings regularly with fresh clean and ensure the soil is consistently moist but well-drained.
Before applying fertilizer to the lawn, it's important to mow it first to clear away any thatch. This allows the fertilizer to make better contact with the soil. When the spring fertilizer makes better contact with the soil, it will be absorbed more easily by the roots of your grass.
Change out your propagation water on a regular basis to maintain healthy root growth. We recommend a water change about once a week. Each time you change out the water, use this as an opportunity to give any of your thirsty plants a drink to close the loop.
The two main nutrients that support excellent root growth in plants are phosphorous and potassium. These two ingredients are extremely helpful in any fertiliser mix that needs to encourage a thick, healthy collection of brand-new roots, or to strengthen and stimulate existing systems.
It's important to keep the soil moist to encourage initial healthy root growth.
Hydroponic Booster Fertilizer - Super Concentrated 4-11-8 Formula - Use with Any Hydroponic or Aeroponic System - Great for Herbs, Veggies, Fruits, and More (8oz)
'Using a greenhouse or a humidity dome will speed up propagation because it will ensure the humidity remains high and the roots when they begin growing don't dry out, as roots drying out will result in propagation failure,' says Julie Bawden-Davis, indoor plant expert at Healthy Houseplants.
Add fresh, tepid water when needed. You can replace the water every few days, or simply top off the vessel with fresh water when it's looking low—as long as there is no murkiness or fungi growing. If the water is murky, we recommend replacing it for the health of the growing root system.
Now you need to transplant your cutting. This is a key moment, taking the plant from life in water to one in soil. Fill a small pot two-thirds full with Miracle-Gro® Indoor Potting Mix. The nutrients and lightweight texture will help your plant adjust nicely.
While fertilizer isn't necessary in the early stages, adding it later can boost growth for long-term water propagation. Using a highly diluted solution ensures that the new roots get the nutrients they need without the risk of over-fertilization.
Perhaps one of the most common mistakes with water propagation occurs once the plant is back in the soil: not watering enough after transplanting. The roots that grow while the cutting is in water are called water roots.
Add a Pothos! I'd heard of using willow as a natural rooting hormone (no idea where to source that however), but didn't know Pothos has this 'super power' too! Just pop a Pothos cutting in with the water with your slow-to-grow cuttings and it helps speed up root development.
In general, fertilize plants when you start to see new growth - leaves, buds, roots, etc. - and when planting transplants. Don't fertilize when plants are very dry or drought-stressed. Water the root area before fertilizing.
Water your lawn a few days before fertilizing so your soil is ready to accept the fertilizer.
Too much harsh sun, too much or not enough water, and using offcuts from plants that are sickly or flowering can also put your cuttings at risk. Once you're in the know about the typical errors gardeners make, you'll be able to take successful cuttings from plants and grow lots of new plants for free.
Another way to reduce water loss is to keep the cuttings in a humid atmosphere – place a clear plastic bag over individual pots or use a propagator with a lid.
Most of the water will be lost through the leaves, so by decreasing the leaf surface you also decrease the amount of water loss. A general rule of thumb is to remove 1/2 to 2/3 of the leaves. Cut remaining leaves in half if they are large.