Guanokalong® is a brand of bat guano. Guano is dried, aged animal droppings used as fertiliser, and this product comes from bats. GK-Organics® is the wider range from the same maker. It includes bat guano as a powder and as a liquid, palm tree ash, worm castings (the material earthworms leave after digesting organic waste) and other dry amendments.
A dry amendment is a solid material that you mix into the growing medium before planting. You do not pour it on with the water at each feed. This topic covers four things. First, how that changes your planning. Second, what to check before you mix a batch. Third, where the product comes from. Fourth, how heat, rain and power cuts in Thailand and Southeast Asia affect it.
How Dry Amendments Feed a Plant
Bottled liquid nutrients reach the roots as soon as you water them in. Dry amendments are slower. You mix them into the soil, and microbes and other small soil organisms then break them down. The nutrients become available to the roots over several weeks.
Because release takes weeks, you make the main feeding decision when you mix the soil, before planting. A mistake is slow to correct. You cannot remove an amendment from the soil the way you can drain and refill a nutrient tank. If the mix is right, though, the pot needs little more than plain water for much of the crop cycle.
This approach is the basis of living soil. That topic compares it with mineral feeding in more detail.
What to do: before you buy amendments, decide which growing medium you will use and how long the plant will stay in that pot. The amount you mix in has to last for that whole period. Knowing it lets you plan the mix instead of correcting it later.
Two Checks Before You Mix a Batch
Guano strength changes from sack to sack
Guano varies with the cave it came from and the season it was collected. A rate that was safe from one sack can burn seedlings from the next one. The damage shows as nutrient burn, with brown, crispy leaf tips and edges.
For this reason, let the mixed soil rest and settle before you plant into it. Do not mix and transplant on the same day.
What to do:
- Start with the rate printed on the label of the sack you have. The rate from your last sack may not suit this one.
- Mix a small test batch first, enough for a few pots. Plant two or three seedlings and watch them closely. If the sack turns out to be strong, only those few plants are damaged, not the whole crop.
- Write down the batch number on the sack, the rate, the mixing date, the planting date and how the test plants looked. When you open the next sack, you can compare instead of guessing.
Soil life has to be active
Nutrients in an amended soil reach the plant only after soil organisms break them down. If those organisms slow down, feeding slows down too, even if the pot is full of guano. Soil temperature and soil moisture therefore control how well the plant is fed. Treat them as part of your feeding plan.
Translator’s note: in Thailand, a pot standing in direct sun heats up quickly, especially a black plastic pot. Soil that dries out completely between waterings also slows soil life. Shade the sides of the pot or use a lighter-coloured pot. Keep the soil evenly moist but not waterlogged. Soil organisms then keep working at a steady pace, and the plant gets a steady supply of food.
Where the Product Comes From
According to the manufacturer, Guanokalong is bat guano from cave deposits on Java (Indonesia) and in Madagascar. It is processed in Aalten in the Netherlands. Part of the raw material comes from this region. Even so, the branded product reaches Southeast Asia as a European import, and it is priced like one.
General farm-supply and orchid-supply sellers across the region also sell guano and guano-type products. If you buy guano this way:
- Ask for an NPK analysis. This shows the percentages of nitrogen (N), phosphorus (P) and potassium (K) in the product. With these figures, you can set a starting rate instead of guessing.
- Ask for confirmation that the material has been composted or heat-treated. Untreated material is more likely to carry disease organisms.
- Avoid guano of unknown origin. Caves and bat colonies are protected in several countries, so material of unknown origin may have been collected illegally.
Translator’s note: in Thailand, fertilisers come under the Fertilizer Act B.E. 2518 (1975), as amended by the Fertilizer Act (No. 2) B.E. 2550 (2007). Before you buy, ask an authorized distributor in Thailand for the registration details and the analysis sheet. The topic on checking that a fertiliser is legal in Thailand explains how to read the label.
Using Guano in a Hot Climate
Faster release
Soil life works faster in heat. A mix that holds a large dose of guano from the start will therefore release its nutrients sooner in Thailand than in Europe. At 30–35 °C, a feeding schedule written for a cooler climate will be wrong if you follow it week by week.
What to do: check leaf colour twice a week. When the leaves start to fade, the plant is running short of food. Note the date it starts. On the next crop, you will know roughly when this mix runs out in your conditions.
Storage
Keep dry guano sealed, dry and out of the sun. In a hot storeroom, damp guano forms hard lumps and spoils.
Translator’s note: in the rainy season, air humidity stays high for weeks, and an open sack absorbs moisture from the air. Store guano in an airtight container with a lid and keep it off the floor. Close it straight after each use. The product then stays loose and usable until the sack is finished.
Teas
A tea here means a liquid fertiliser made by soaking an organic material, such as guano or worm castings, in water. An air pump often bubbles air through it while it brews. The topic on compost tea explains the method. At 30 °C, a nutrient-rich organic liquid like this turns sour quickly.
What to do: mix only as much tea as you will use within one day.
Translator’s note: a power cut stops the air pump, and the tea spoils even faster. If power cuts are common where you grow, brew smaller amounts so you lose less when one happens. If a tea smells sour or rotten, do not use it on your plants.
Dust
Dry guano can carry the fungus that causes histoplasmosis. Histoplasmosis is a lung infection caught by breathing in fungal spores from bird or bat droppings. Fine dust from a sack is the main way those spores reach your lungs.
What to do:
- Wet the guano lightly before you handle bulk material. Damp dust stays in the sack and does not get into the air you breathe.
- Wear a fitted particulate respirator when you pour out sacks. Use one rated at least N95 or P2. A cloth or surgical mask does not filter out fine spores well. For large amounts of bat or bird droppings, NIOSH advises a higher level of protection: a full-facepiece respirator with 100-series filters, or a powered air-purifying respirator (PAPR).
Translator’s note: if you get a fever, cough or chest pain in the days or weeks after handling guano, see a doctor. Tell the doctor that you handled bat guano, because it helps them consider the right cause.
Share Your Mix Below
When this board was set up, it had no reference articles. What it needs most are recipes and mix reports from members. If you use a GK-Organics product, post a reply under this topic with these details:
- the product and the rate per litre of soil
- how long you let the mix rest before planting
- your growing medium and pot size
- the temperature where you grow
- how the test plants and the full crop turned out
Questions are welcome in the same thread. For background on the method, start with the living soil and growing media topics linked above.