As the coffee harvest season draws to a close, this is the ideal time for farmers to select good coffee seeds for the next crop. Below is a detailed guide—shared by Y5cafe—on how to propagate the two main coffee types grown in Vietnam: Arabica (cà phê chè) and Robusta (cà phê vối), using both sexual (seed) and asexual (clonal) methods.
Coffee as a Perennial Crop
Table of Contents
Coffee is a long–lived industrial crop, with an economic cycle of over 40 years depending on variety, cultivation conditions, care and production objectives. To ensure consistently high economic returns, proper variety selection and propagation techniques are crucial.
I. Propagation Materials
Vietnam mainly grows two species with distinct genetic and ecological traits, requiring different propagation methods:
1. Arabica (cà phê chè)
Arabica is self-pollinating. Common cultivars such as Bourbon, Typica, Caturra, Catuai, Mundo Novo, Catimor, TH1, etc. are genetically pure, so they are usually propagated by seed. To avoid cross-pollination, each seed garden should contain only one variety and be isolated from others.
Recently, the Western Highlands Agriculture and Forestry Science Institute has introduced F1 Arabica hybrids. Because commercial F1 seed production is not yet feasible, these are currently propagated by clonal methods.
2. Robusta (cà phê vối)
Robusta is strictly cross-pollinating and cannot produce true-breeding seed lines. Seed supplied for Robusta production comes from two- or multi-line hybrids and is unsuitable for seed gardens. To produce such hybrid seed, male and female parent plants—propagated clonally—must be planted in alternating rows to ensure cross-pollination and isolated from other Robusta fields.
Since bean size is largely inherited from the mother, select mother clones with large beans for seed production. Apart from hybrid seed, Robusta propagation in practice relies mainly on vegetative (clonal) methods.
II. Sexual Propagation (by Seed)
2.1 Processing, Storing and Transporting Seed
Harvest cherries at full ripeness—avoid overripe, underripe, dry or malformed fruit. Pulp immediately; do not leave overnight. Use a disc, drum or conical pulper. For small volumes, manual pulping is possible. Remove the mucilage by fermenting 12–20 hours depending on climate, stirring 2–3 times, then washing clean.
Alternatively, wash immediately using a 2–3 % solution of Na₂CO₃, NaOH or NH₄OH. Dry seeds in the shade until surface moisture is gone.
Coffee seed is recalcitrant—it quickly loses viability—so sow within 7–15 days. If storage is necessary, spread seeds 10 cm thick on mats or clean concrete in a cool, airy place. Keep humidity 85–90 %, seed moisture 20–22 %, temperature 22–25 °C; under these conditions germination remains above 80 % for 2–3 months. Beyond this period viability drops sharply.
During transport, use jute or PE bags ≤ 30 kg each; protect from sun and rain. If internal bag temperature reaches ~40 °C, open and aerate. Dust seed with a dry fungicide (e.g., Benomyl, Captan, Captafol) to prevent mold.
2.2 Nursery Site
Choose a well-drained, wind-sheltered, accessible site near water. Clear weeds and debris, loosen the top 10–15 cm of soil. Install a shade house about 2 m high with adjustable cover (coconut fronds, straw, bamboo mats or shade net) to regulate light. Initially allow only 20–30 % of natural light.
Beds should run north–south, 1.0–1.2 m wide and 20–25 m long, with 35–40 cm paths. Provide drainage ditches and windbreaks.
2.3 Polybags
Use 15–17 cm × 23–25 cm plastic bags perforated with eight 0.5 cm holes 2–4 cm above the base. Fill with a mix of 0.7–0.8 m³ topsoil (0–20 cm depth), 0.2–0.3 m³ well-rotted manure and 5–6 kg fused phosphate per m³—enough for 800–900 bags. Firm the mix, leaving 1 cm from the rim.
2.4 Pre-germination and Sowing
a. With parchment intact
Soak seed 18–24 h in limewater (1 kg lime/50 l water) preheated to 55–60 °C. Wash off mucilage and discard empty or moldy seed. Place seeds between layers of clean banana leaves or sacks under straw to keep warm and moist. Water with 30–40 °C water if dry. After ~5 days, when radicles emerge, sow immediately.
b. With parchment removed
For small lots, sun-dry until parchment is brittle, hand-rub to remove, soak in 50–55 °C water for 16–18 h, wash and pre-germinate as above. Monitor carefully to prevent rot.
c. Sowing in bags
Using a finger or stick (~1 cm diameter), make a 1.5–2 cm deep hole in the center of each bag. Place the sprouted seed with radicle down, cover lightly and mulch with rice husk or straw.
If germinated seed is ready but bags are not, sow temporarily in germination beds (rows 1 cm apart, seeds 3–4 cm apart) under a thin sand layer and mulch, then transplant carefully when seedlings reach the “matchstick” stage.
2.5 Seedling Care
Water every 2–3 days. After 1–2 pairs of true leaves, feed with 0.1–0.15 % urea; after 3 pairs increase to 0.2–0.3 %. Always rinse with clean water after fertilizing. Weed promptly and break soil crusts.
Adjust shade:
– From emergence to first true leaf: 15–20 % light.
– 2–3 pairs leaves: 30–40 %.
– 3–4 pairs: 50–70 %.
– One month before field planting: full sunlight.
Seedlings are ready for transplanting at 20–30 cm tall with 5–6 pairs of true leaves and stem diameter ≥ 3 mm.
III. Vegetative (Clonal) Propagation
Common practical methods are grafting and cuttings, which require moderate skill and simple tools.
1. Grafting
1.1 Scion Gardens
Establish scion gardens near the nursery for easy management and harvesting. Prepare 1.2–1.6 m wide beds, 10–20 m long. Incorporate 15–20 kg well-rotted manure + 2–3 kg phosphate per m². Plant at the start of the rainy season. After 3–4 months, cut plants back to 10–15 cm above ground to stimulate shoots, leaving a pair of basal leaves. Harvest scions once shoots have at least two nodes.
1.2 Technique
The most suitable method is top-grafting.
– For 4–6-month-old rootstocks: Cut off the tip 3–4 cm above a leaf pair and split downward 2–3 cm. Shape the base of the scion into a wedge 2–3 cm long. Insert the scion so cambium layers match, then tie firmly with 1 cm wide plastic tape. If humidity is low, cover the graft with a plastic sleeve for the first week. Remove the tie after about one month when the scion has taken and produced new leaves.
– For very young rootstocks at the “matchstick” stage, the procedure is similar but carried out earlier, often to impart nematode resistance by grafting Arabica onto robusta rootstocks.
2. Cuttings
2.1 Propagation Bed
Build a propagation frame of brick, wood or bamboo covered with glass or clear plastic to maintain 24–28 °C and near-saturated humidity with 20–25 % diffused light. Place under a 2–2.5 m shade house. For the first two weeks shade 75–80 %, then gradually reduce to about 40 %.
Use clean sand, sawdust, rice husk or decomposed coffee husk as the medium over a 20–30 cm layer of gravel for drainage. Disinfect with a non-copper fungicide (e.g., Zineb, Mancozeb).
2.2 Preparing Cuttings
Select upright shoots with 6–8 nodes, semi-mature, from scion gardens. Harvest before 9 a.m. Cut into 5–6 cm sections with one leaf pair; trim leaves to 1/3–1/4 size. Cut the base into a wedge and insert 400–500 cuttings per m². Mist twice daily and remove fallen leaves or rotting cuttings promptly.
2.3 Potting and Nursery Care
After 2.5–3.5 months, when cuttings have 7 cm roots with 1–3 main roots, transplant into 20 × 30 cm polybags prepared as for seed seedlings. If a cutting has multiple main roots, keep only one strong root trimmed to 7–10 cm.
Provide full shade at first and adequate moisture. After 4–5 months, when plants are 17–20 cm tall with about 5 pairs of leaves and 1–2 pairs of lateral branches, they are ready for field planting.
By carefully following these sexual and clonal propagation methods—proper seed handling, nursery preparation, and careful grafting or cutting techniques—farmers can produce healthy, uniform coffee seedlings, laying the foundation for high yields and sustainable coffee production.