Process of preparing soil for planting coffee seedlings

The soil in the pot determines the roots of coffee seedlings within 6-8 months of the nursery. Instructions for choosing disease-free topsoil, mixing organic matter, treating nematode fungi, potting and checking before sowing.

Summary: Good coffee seedlings start from good soil. If the potting soil taken from an old coffee orchard has nematodes or mycorrhizal fungi, the seedlings may look green at first but the roots are weak and will easily die in the orchard. This article guides the process of preparing potting soil: choosing soil source, drying — processing, organic mixing, potting and arranging pots in the nursery.

Applies to: Robusta coffee nurseries in the Central Highlands, both nursery seeds and grafted trees.

Duration: Prepare the soil 2-4 weeks before sowing.

Difficulty level: Basic but needs to be clean and even.

Estimated additional costs: 3-8 million VND for potting soil, organic materials and preparation labor per 10,000 pots, depending on material source.

Requirements of potting soil

The potting soil must meet four requirements:

• Make it loose so that young roots can eat straight down.
• Moderately moisturizing but not watery.
• Clean disease sources: limit nematodes, root rot fungi, and grass sprouts.
• Light nutrition, not too salty, not too hot.

Seedlings stay in pots for 6-8 months. A bad potting soil will limit the root system from the beginning, even if good fertilizer is applied later.

Select land source

Priority is to get topsoil 0-30 centimeters in places:

• The soil is loose, has a lot of humus, and has not yet planted diseased coffee.
• Do not take close to barns, landfills, or places with chemicals.
• Do not take soil from old coffee orchards, orchards with yellow leaves, root rot or nematodes.
• Do not use heavy clay, alum soil, or salty soil.

If you must use soil near coffee growing areas, it should be treated carefully and should be mixed with loosening material.

Mixing ingredients

Reference formula:

• 70 percent of topsoil is loose.
• 20 percent thoroughly composted compost.
• 10 percent smoked rice husks, treated coconut fiber or suitable loosening material.

Can add:

• Light fused phosphate.
• If the soil is acidic, mix lime powder 10-15 days in advance.
• *Trichoderma* if the organic matter is rotten and moist enough.

Do not use fresh manure, fresh coffee husks or unprocessed coconut fiber. These materials can easily heat up the pots, keep fungi away or cause yellowing of seedlings.

Treat the soil before potting

Dry and smash

• Let the soil dry for 5-7 days in mild sunlight.
• Small dams, rocks, tree roots, large lumps of soil.
• Sift through a mesh if making a large nursery.

Soil that is too fine can easily squash; Too lumpy soil causes uneven potting and bent roots.

Treating pathogens

• Mix lime if the pH is low or the soil is at risk of fungus.
• Incubate the mixed soil for 7-15 days before potting.
• Keep moist enough to stabilize microorganisms.

If the soil is suspected of having nematodes, do not try to use it for seed pots. Nematode-infected gourds are a way to bring the disease to the whole new orchard.

Choose a polybag

Common pot size for coffee varieties:

• Diameter 13-14 centimeters.
• Height 23-24 centimeters.
• There are drainage holes on the bottom and sides.

A bulb that is too small causes the roots to quickly touch the bottom and easily twist. Too large gourds take up land, labor and are difficult to transport.

Potting

Process:

• Put soil into the pot in layers, compact gently.
• Do not compact too tightly as the soil will squash.
• The mouth of the bulb is 1-2 centimeters lower than the edge of the bag for easy watering.
• The bulb stands straight, not distorted.
• Check drainage after test watering.

The soil in the pot needs to be compact enough to not break when moved, but still loose enough for the roots to penetrate.

Arranging pots in the nursery

• Choose a high, well-drained foundation.
• Place the pots into beds 1-1.2 meters wide for easy care.
• Leave a drainage ditch in the middle of the bed.
• Build a pergola to reduce sunlight by 50-60 percent in the early stages.
• Do not place bulbs directly where rainwater falls from roofs or slopes.

The nursery must be clean of weeds, easy to water and easy to check for diseased plants.

Check before sowing

Before sowing seeds or transplanting seedlings:

• [ ] The potting soil is moist enough, not soggy.
• [ ] It's not hot, there's no smell of fresh manure.
• [ ] Irrigation water can drain through the bottom.
• [ ] There are no ants, termites, or insects nesting in the gourd.
• [ ] The potting bed has a sunshade and drainage ditch.

If you try watering and the water stays on the surface of the bulb for a long time, the soil is too stuffy. It is necessary to mix the loosening material before sowing.

Common mistakes

Taking soil from a diseased coffee orchard: brings nematodes and fungi into the pot.

Using unfertilized fertilizer: yellow seedlings, burned roots, hot smell in pots.

Compacting the pot too tightly: roots lack oxygen, slow growth.

The sky has no drainage hole: heavy rain causes mass flooding.

Do not shade after sowing: the potting soil is hot, the sprouts are weak and the survival rate is low.

Take notes

• Land source and date of land acquisition.
• Mixing ratio.
• Amount of lime, phosphate, organic matter, microorganisms used.
• Date of filling, number of bulbs.
• Proportion of gourds with fungus, dead plants, and stunted plants after sowing.

Taking notes helps you know which potting formula produces the healthiest plants, especially when breeding multiple crops.

Related articles

• Technique of brewing and growing coffee beans directly in potting soil
• Watering techniques for coffee seedlings when nursery
• Preparing robusta coffee seedlings
• Technology for planting new coffee trees