“Cuttings”
(or “clones”) are a popular method of propagating plants. A cutting is a
plant part removed from a 'stock' or donor plant that will develop roots and
shoots when placed in soil under favourable conditions.
In comparison to propagation via seed, cuttings
offer some lucrative benefits:
1.
Propagating from cutting is much quicker than growing from seed.
2.
Cuttings produce a plant generally having the same genetic characteristics
as the stock plant e.g. same appearance, size, yield, etc. This cannot be
achieved using seeds.
3. Cuttings taken from the most recent
growth will produce plants that take less time to reach biological maturity.
Commercial fruit growers use cuttings to minimise the lengthy non-fruiting
phase associated with seed propagated plants. Where artificial
lighting is used, cuttings can be switched to flowering much sooner by
simply changing to a “redder” light spectrum (e.g. HPS lamp). This is
beneficial because the crop cycle is faster, and plants can be kept much
shorter
which makes more efficient use of both light and space.
Stem cuttings: The most appropriate
cutting material will vary between species, however, most species can be
propagated using 'stem cuttings'. Stem cuttings possess stems, leaves and
buds (Fig 4.3). Roots grow from the basal wood (Fig
4.1) and shoots grow from the buds.
Procedure for producing cuttings
Step 1. Thoroughly sterilize all
hardware that is likely to contact cuttings.
Step 2. Pre-soak
growing medium (e.g.
Rockwool) by immersing in TwinTech
Fertilizer to ensure excess ‘alkalinity’ is removed. Gently
squeeze to drain excess nutrient.
Step 3. (Fig 4.2) To increase the
success rate of cuttings, use a ‘heat mat’ and ‘propagation li
d’
to maintain root (see 'Bottom Heat' below) and air temperature at 20-25oC (68-77oF)
and relative humidity at ~80%. Use cool white fluorescent lighting
timed to run 18 hours per day. Ensure this environment is established prior
to planting cuttings.
Step 4. Select a plant that has
been well maintained, has favourable characteristics and is free of disease.
The cutting material must be of 'semi-hard' wood i.e. wood that is beginning
to turn hard. Avoid plants that are well into the flowering stage.
Step 5. Using secateurs (or
scalpel) remove a 'lateral' (side branch) that has at least 3 sets of leaves
(Fig 4.3). Immediately place the cut end into lukewarm water.
Step 6. Using a scalpel, trim
cuttings as per Fig 4.4a: (1) Remove bottom set of leaves**; (2) Cut through
stem at a 45o angle below where the lowest set of leaves were.
Note, if remaining leaves are too large these should be cut in half.
Step 7. Immediately immerse region
(3) into TwinTech Starter (Fig 4.4a &
4.4b). Punch a snug hole in the medium, deep enough to accommodate region
(3). Push cutting right to the base of the pre-made hole then press medium
against the stem (Fig 4.4c). Do not re-water until necessary.
Step 8. Mist cuttings daily using
water (or TopFert), and water the
medium as required using a combination of TwinTech Fertilizer and
TwinTech Plus (EC ~0.8mS). To
avoid stem rot and disease, never allow medium to remain waterlogged.
Diligently remove any dead leaves or cuttings as these are an ideal host for
fungi. Also, remove any floral buds that form.
Step 9. Depending on the plant
variety, roots usually develop within 7-10 days. Once this occurs,
gradually expose cuttings to their proposed environment. Note that a
sudden change in humidity, nutrient strength, light intensity or temperature
might kill them. Therefore, gradually increase nutrient strength to EC
~1.3mS. Also, remove the propagation lid for ~30 minute periods
initially, increasing the frequency over the course of a few days (or as
required) until the cuttings are ready to be
planted into their proposed environment.
**If the growing medium is sufficiently
deep, it is possible to get better survival rates by having a second set of
leaf “nodes” below the medium’s surface (Fig 4.4d). When planting, position
these nodes just below the surface of the medium.
Bottom heat
for cuttings
Bottom heat is highly beneficial for 'cuttings'
because it increases the respiration rate at the 'cut' end. Respiration
rate is critical because it produces energy to form roots. Note, heating the
air is counter productive for root production in cuttings because this
increases the rate of transpiration causing cell dehydration (i.e. no
available roots to replace the lost water) and increased shoot growth (which
depletes carbohydrate reserves).
[Growers Guide Main Index]
Related topics
"Plant
propagation":
Cuttings (clones) |
Seedlings |
Mother (Donor) Plants
Transplanting
cuttings & seedlings |
Mediums (substrates)
for cuttings & seedlings
