How much food can one hydroponic tower produce per month in Bangkok? Yield log across 6 crop cycles

Key takeaways

Across 6 logged crop cycles in the same tower in Bangkok, total fresh weight harvest per cycle ranged from 1,240g to 2,180g, with the lowest yields in hot season cycles and the highest in cool season cycles run at the same port density and with the same nutrient protocol.

Per-port yield for loose-leaf lettuce in cool season averaged 68g of fresh weight at harvest, falling to 43g per port in hot season, a 37 percent reduction from the same variety and seed source with no change to nutrient formula or tower hardware.

Monthly yield from a single tower running continuous back-to-back 25 to 28 day lettuce cycles is realistically 1,600 to 1,900g of fresh weight in cool season and 1,000 to 1,300g in hot season, not the 3,000 to 5,000g figures that appear in manufacturer marketing materials.

Herb cycles, specifically basil, produced lower total fresh weight per cycle than lettuce but higher value per gram at Bangkok market prices, making a mixed-crop tower running 60 percent lettuce and 40 percent basil by port count a better economic configuration than a single-crop setup.

The single variable that predicted yield outcome more reliably than any other across the 6 cycles was days spent with reservoir temperature above 28 degrees Celsius, which correlated with both per-port fresh weight and cycle length extension better than EC, pH consistency, or light hours.

TL;DR

One tower in Bangkok produces meaningfully less than the marketing says and more than a skeptic would guess, but only in the right months. Cool season yields are real and consistent. Hot season yields are real and disappointing. The growers who report good numbers year-round are either running climate control that most apartment setups do not have, or they are only counting their good cycles. Logging every cycle, including the bad ones, is the only way to know what your tower actually produces.

The harvest that made me start the yield log

The first time I weighed a full tower harvest properly, not just eyeballed it, I had been growing for about four months. I had a kitchen scale, a tray, and a notebook. The cycle had gone well by the standards I was using at the time, which were mostly visual. The canopy looked full. The heads looked like lettuce. I pulled everything, washed it, and weighed it in batches. Total fresh weight: 1,380g. I had 28 ports in the tower. That was just under 50g per port average. I had been telling people my tower produced roughly two kilograms per harvest. That was not wrong exactly. It was also not the controlled comparison I needed to understand what was driving yield up or down from cycle to cycle.

I started the yield log that week. Not because 1,380g was bad. I did not know yet whether it was bad or good. I started it because I had no reference point for what the same tower should produce under better or worse conditions, and I was making decisions about which crops to grow, when to grow them, and whether the tower was worth the inputs without any actual data to anchor those decisions. Six cycles later, the log had answered the questions I had not known how to ask. The yield gap between my best and worst cycle was 940g. That gap had a name: it was called March to May.

Why Bangkok does not give you one yield number

A hydroponic tower in Bangkok is not operating in a stable environment. It is operating in a city with two functionally distinct growing seasons running through the same hardware. Cool season, roughly November through February, brings ambient temperatures that allow reservoir water to stay in a range where dissolved oxygen is adequate, root function is efficient, and nutrient uptake proceeds close to the rate the plant is capable of. Hot season, March through May and into June, pushes reservoir temperature into a range where dissolved oxygen drops, root membrane function degrades, and the plant diverts energy into stress responses rather than biomass accumulation. The tower does not change. The growing environment inside it changes significantly.

In the cycle 3 yield log entry, a cool season loose-leaf lettuce run, reservoir temperature averaged 24.3 degrees Celsius across the 26-day cycle. Total harvest: 1,920g across 28 ports, or 68.6g per port average. In cycle 5, the same variety, same seed lot, same nutrient formula, same tower, reservoir temperature averaged 29.1 degrees Celsius across a 30-day cycle. Total harvest: 1,240g, or 44.3g per port. The four-day cycle extension did not recover the yield gap. It narrowed it slightly compared to cutting the cycle at 26 days, but the biomass that was not built during the heat-stressed growth phase did not appear just because the cycle ran longer. The yield was lower because the growing environment was worse, from day one to harvest.

The mechanism connecting reservoir temperature to yield operates through dissolved oxygen availability at the root zone. At 24 degrees Celsius, water holds approximately 8.4 mg/L of dissolved oxygen at saturation. At 30 degrees Celsius, that ceiling drops to approximately 7.5 mg/L, and in a plant-active system with active root respiration, actual DO sits well below saturation at both temperatures. The practical effect is that root cells at elevated temperature are working harder to take up nutrients while receiving less oxygen to power that work. The result at the harvest level is not a dramatic crop failure. It is a quiet, consistent yield reduction that runs across the entire cycle and shows up most clearly when you are weighing crops and keeping the numbers in a log rather than assessing by eye.

A full canopy at day 14 does not predict a good harvest

Hot season cycles in Bangkok consistently produce faster early canopy development than cool season cycles. Leaf expansion in the first 10 to 14 days is more rapid at higher temperatures, which means a hot season tower at day 14 often looks better than a cool season tower at the same stage. This is a stress response, not a performance signal. Elevated temperature accelerates shoot growth initially while root zone stress is still building. By day 18 to 21, the root zone cumulative stress has caught up with the canopy and above-ground growth rate stalls. The cool season tower, which looked slightly behind at day 14, catches up and overtakes during the second half of the cycle when its root zone is still functioning efficiently.

In the yield log across cycles 1 through 6, the two cycles with the fullest-looking canopies at the day 14 visual check were cycles 4 and 5, both hot season runs. Cycle 4 produced 1,390g at harvest. Cycle 5 produced 1,240g. Cycles 2 and 3, which looked slightly sparser at day 14, produced 1,870g and 1,920g respectively. The visual check at two weeks has inverted predictive value in Bangkok conditions. The cycle that looks best at day 14 is often the one that disappoints most at harvest.

If the tower looks full and healthy at the two-week mark, the harvest will be close to the target weight because the plant growth is clearly on track.

The yield log: 6 cycles, same tower, real numbers

26-day cycle. 28 ports. Reservoir temperature averaged 24.8 degrees Celsius. Total harvest fresh weight: 1,380g. Per-port average: 49.3g. Notes: First properly weighed cycle. Lower per-port weight than subsequent cool season cycles likely reflects early-operation nutrient calibration rather than environmental factors. pH was managed manually once daily, which in retrospect was adequate for cool season drift rates. No tip burn. Germination rate: 89 percent.

Cycle 1: Loose-leaf lettuce, November, cool season entry

Even an under-optimised first cycle in cool season outperformed the best hot season cycle in the log. The environmental baseline of cool season Bangkok is forgiving enough that early operational errors do not produce catastrophic yield reduction.

25-day cycle. 28 ports. Reservoir temperature averaged 23.6 degrees Celsius. Total harvest fresh weight: 1,870g. Per-port average: 66.8g. Notes: Best-managed cool season lettuce cycle in the log. pH corrected twice daily after a drift event in cycle 1 showed the once-daily schedule was marginal. EC held within 0.2 mS/cm of target throughout. No tip burn. Germination rate: 96 percent. This cycle established the cool season performance baseline for the tower.

Cycle 2: Loose-leaf lettuce, December to January, cool season

When cool season conditions, competent pH management, and a stable nutrient profile align, 66 to 68g per port is a repeatable fresh weight figure for loose-leaf lettuce in this tower configuration. This is the number to use as a baseline for evaluating whether any subsequent cycle underperformed and by how much.

28-day cycle driven by basil maturity timeline. 18 lettuce ports at 25 days: 1,180g total, 65.6g per port. 10 basil ports at 28 days: 340g total, 34g per port. Combined fresh weight: 1,520g. Notes: Basil per-port weight lower than lettuce but market value per gram at Bangkok fresh markets approximately 3.5 times higher than lettuce at the time of harvest. Mixed crop configuration produced lower total fresh weight but higher gross value per cycle. Lettuce yield held consistent with cycle 2, confirming cool season baseline.

Cycle 3: Mixed crop, 18 lettuce ports and 10 basil ports, January to February, cool season

Total fresh weight is not the right metric for a mixed-crop tower. Value per cycle is. The 340g of basil from 10 ports generated comparable or greater gross value to the 1,180g of lettuce from 18 ports depending on sale channel. Growers optimising for yield weight alone will systematically undervalue herb ports.

29-day cycle. 28 ports. Reservoir temperature averaged 27.4 degrees Celsius, rising from 25.1 at cycle start to 29.8 by day 20. Total harvest fresh weight: 1,390g. Per-port average: 49.6g. Notes: Tip burn appeared on inner leaves from day 19 onward affecting approximately 35 percent of heads. Trimmed affected tissue before weighing. Germination rate: 84 percent. Cycle extended 3 days beyond cool season schedule without recovering to cool season weights. First hot season cycle in the log.

Cycle 4: Loose-leaf lettuce, March to April, hot season onset

The transition into hot season is not a cliff. Cycle 4 is the warning cycle, where conditions are deteriorating but have not yet reached peak hot season stress. Per-port weight dropped 26 percent from the cycle 2 baseline. Growers who run this cycle without the comparison data will not recognise it as degraded performance. It looks like a normal, slightly disappointing harvest.

30-day cycle. 28 ports. Reservoir temperature averaged 29.1 degrees Celsius across the cycle, reaching 31.4 degrees Celsius on the hottest days. Total harvest fresh weight: 1,240g. Per-port average: 44.3g. Notes: Tip burn on greater than 50 percent of heads. Germination rate: 71 percent, requiring replanting of 8 ports at day 4. Cycle extended to 30 days without yield recovery. Worst-performing cycle in the log. Root browning visible at harvest on approximately 40 percent of root mass inspected.

Cycle 5: Loose-leaf lettuce, April to May, peak hot season

Peak hot season in Bangkok with no active reservoir cooling produces a 35 percent yield reduction from the cool season baseline in this tower. This is not an unusual event or a management failure. It is the predictable outcome of running the same hardware in a 29-degree-Celsius reservoir with no temperature intervention. Cycle 5 is what the tower produces in April without mitigation. Knowing that number is what makes a reservoir cooling decision calculable.

26-day cycle. 28 ports. Reservoir temperature averaged 25.2 degrees Celsius. Total harvest fresh weight: 1,810g. Per-port average: 64.6g. Notes: Performance returned to within 3 percent of cycle 2 baseline as soon as ambient conditions allowed reservoir temperature to drop. No tip burn. Germination rate: 93 percent. Confirmed that the yield reduction in cycles 4 and 5 was environmental, not cumulative tower degradation or nutrient formula drift.

Cycle 6: Loose-leaf lettuce, October to November, cool season re-entry

The recovery to near-cycle-2 performance in cycle 6 is the most important data point in the log for a grower trying to understand whether hot season underperformance is fixable or structural. It is environmental. The tower hardware, nutrient system, and seed source are all capable of cool season performance. The constraint is temperature. Anything that addresses reservoir temperature in hot season is addressing the actual yield ceiling, not a secondary variable.

Plant Mood grow log data, 2023 to 2024

What the yield number does not tell you on its own

Every fresh weight figure in the yield log above is trimmed weight: roots removed, outer damaged leaves removed, tip-burned tissue trimmed before weighing. Gross weight before trimming runs 8 to 14 percent higher in cool season cycles and 15 to 22 percent higher in hot season cycles where tip burn and damaged outer leaves are more prevalent. Growers who report harvest weights without specifying whether they are gross or trimmed are giving a number that cannot be compared to anyone else's data. Hot season cycles lose a larger proportion of gross weight to trimming, which means the yield gap between seasons is larger in usable food terms than the fresh weight comparison suggests.

Trimmed weight versus gross weight

A 26-day lettuce cycle does not map cleanly to a calendar month. Running back-to-back cycles with no gap between harvest and replant produces approximately 14 cycles per year, or 1.17 cycles per calendar month on average. Reporting yield as monthly production requires accounting for cycle length variation across seasons, since hot season cycles extend to 29 to 30 days, reducing the number of cycles completable per month. The real monthly yield in cool season is approximately 1.17 multiplied by cycle yield, which means a 1,870g cycle 2 result translates to roughly 2,190g per calendar month. In hot season at 30 days per cycle, 1,240g per cycle translates to roughly 1,240g per calendar month. The per-month gap between seasons is larger than the per-cycle gap.

Per-cycle weight versus per-month yield

The yield log numbers above are based on actual planted ports producing at harvest, not 28 ports at theoretical maximum. In hot season cycles where germination dropped to 71 to 84 percent, 4 to 8 ports were either empty or significantly underdeveloped at harvest. Those ports are unproductive for the entire cycle. Growers who quote per-port yield averages across all ports including vacant ones understate the performance gap between germination rates. A tower running at 84 percent germination is effectively a tower with 23.5 productive ports, not 28. Yield per productive port is a more useful performance metric than yield per total port when germination varies.

Germination failure and port vacancy

Tower manufacturer yield claims typically reference maximum ports at full density, optimal nutrient conditions, controlled temperature, and a high-yielding variety under artificial lighting calibrated for that variety. A 40-port tower marketed as producing 4 to 5 kg per harvest is describing a ceiling that requires every variable to align simultaneously. In a Bangkok apartment without active climate control in hot season, the floor is what matters more than the ceiling for planning purposes. The floor is approximately 40 to 45g per port in peak hot season for loose-leaf lettuce. Any business or household food production plan built on the manufacturer ceiling will be wrong for at least four months of every year.

The marketing yield ceiling

What the yield log suggests is coming for Bangkok apartment growers

Seasonal yield adjustment factors specific to Bangkok will become standard reference data in Thai urban farming communities within 3 years, replacing generic tropical climate yield estimates that do not account for the cool season versus hot season split

The current state of yield information available in Thai for Bangkok apartment growers is dominated by manufacturer marketing figures and generic tropical climate advice that treats Bangkok as uniformly warm. As more growers log actual cycle data and share it in Thai-language communities, the pattern that cool season and hot season produce structurally different yields from the same hardware will accumulate enough documented examples to become a shared reference point. The shift will be driven by growers who logged their first bad April cycle and went looking for an explanation, found nothing specific to Bangkok, and started documenting it themselves.

Look for Thai-language hydroponic growing resources, Facebook groups, or YouTube channels that publish seasonal yield comparison data specific to Bangkok apartment conditions and cite cool season versus hot season adjustment factors by 2027. If no such resource exists with documented cycle data by that date, the prediction does not hold on timeline.

Passive reservoir cooling approaches adapted for Bangkok apartment constraints will become the most-shared practical intervention in the local growing community within 4 years, as the yield cost of unmanaged hot season reservoir temperature becomes more widely documented

Currently, the most common advice for hot season underperformance in Bangkok hydroponic communities is to wait it out, choose heat-tolerant varieties, or reduce light hours. These interventions address secondary variables. The primary variable is reservoir temperature, and the yield data makes the cost of ignoring it calculable once growers are logging harvest weights across seasons. As that documentation accumulates, the demand for practical reservoir cooling solutions adapted to apartment constraints, specifically low-cost, low-space, low-noise approaches, will grow. The prediction is that this demand will produce widely-shared practical solutions, not that anyone will manufacture a product specifically for Bangkok apartment growers.

Check whether reservoir temperature management for Bangkok apartment towers is among the top discussed practical interventions in Thai urban farming communities by 2028, as measured by post frequency and engagement in the largest Thai hydroponic growing groups. If variety selection and light management remain the dominant recommended interventions without reservoir temperature appearing as a primary topic, the prediction is wrong.

What growers say about tower yield versus what the log shows

My tower does not produce anywhere near what the manufacturer says it should. I followed the instructions and the yield is much lower than the marketing promised.

Manufacturer yield figures describe a performance ceiling under controlled conditions that Bangkok ambient temperatures do not provide for most of the year. The gap between the marketing number and the actual harvest is not a management failure in most cases. It is the structural consequence of running hardware rated for optimal conditions in a climate where optimal conditions exist for roughly four months per year without active temperature management. The fix is not better management of the same system. It is either accepting the seasonal yield reality, or adding reservoir temperature control to close the gap in hot season.

My yields have been getting worse over successive cycles and I do not know if it is the tower, the seeds, or something I am doing differently.

If the decline follows the calendar and is worse between March and June than between November and February, it is almost certainly seasonal, not progressive tower degradation or seed quality decline. The yield log pattern across cycles 1 through 6 showed recovery to near-baseline in cycle 6 after two underperforming hot season cycles, confirming that what looks like progressive degradation is often seasonal variation being observed across insufficient cycles to see the recovery. Log harvest weight, cycle dates, and reservoir temperature average for every cycle. Three cycles of that data will usually tell you whether the decline is seasonal or structural.

I grow basil and herbs, not lettuce, and the yield weights I see in online comparisons are not relevant to what I am growing.

Correct. Herb yields measured in fresh weight are structurally lower than lettuce yields for the same port count because herb crops have lower water content and different growth architecture. The relevant metric for a herb tower is value per cycle rather than weight per cycle. In cycle 3 of the yield log, 10 basil ports produced 340g of fresh weight compared to 18 lettuce ports producing 1,180g. But the basil gross value at Bangkok market prices was comparable to or exceeded the lettuce gross value depending on sale channel. Any yield comparison between herb and leafy green towers that uses fresh weight as the only metric will systematically undervalue the herb tower.

How to build a yield log that actually tells you something

Any grower who has not yet started tracking harvest weight

Start with a kitchen scale accurate to 1g, a notebook or spreadsheet, and a commitment to weigh every harvest from the same tower in the same way. Record: cycle start date, crop variety, seed source, total ports planted, number of ports that germinated successfully, harvest date, trimmed fresh weight total, and average reservoir temperature for the cycle if you have it. Nothing else is required to build a useful baseline. Do not wait until your monitoring setup is complete. Start weighing now.

After 3 cycles, you have a baseline. After 6 cycles spanning both cool and hot season, you have a seasonal comparison. After 12 cycles, you have enough data to make informed decisions about crop selection, timing, and whether any equipment or protocol change actually improved yield or just coincided with a better season.

Growers who have yield data but no seasonal comparison

Plot harvest fresh weight per port against cycle start month. If the data spans a full year, the seasonal pattern will be visible without statistical analysis. A decline in per-port weight of 20 percent or more between your November to February cycles and your March to May cycles that recovers in October to November is a seasonal signal, not a management problem. Identifying that pattern removes the temptation to change nutrient formulas, switch seed sources, or replace hardware during the decline phase.

A visual confirmation of whether yield variation is seasonal or random. Seasonal variation is predictable and partially manageable. Random variation points toward inconsistent management variables that are worth investigating. The two look different when plotted against the calendar.

Growers trying to estimate monthly food production for household planning

Use trimmed fresh weight per cycle divided by cycle length in days, then multiply by 30 to get monthly yield equivalent. Apply a cool season figure and a hot season figure separately rather than an annual average. An annual average will overstate what the tower produces during the four worst months and lead to household supply planning that is wrong when it matters. For Bangkok loose-leaf lettuce in a 28-port tower without active reservoir cooling, plan for 1,600 to 1,900g per month in cool season and 1,000 to 1,300g per month in peak hot season.

A household food production estimate that holds across the year rather than one that matches reality in December and disappoints in April. Seasonal planning prevents the common experience of being surprised by hot season yield decline every year because the annual average figure obscured the seasonal split.

Growers running a mixed crop tower and trying to optimise port allocation

Track value per cycle rather than weight per cycle for each crop type. Assign a conservative Bangkok market price per gram to each crop you grow, multiply by average trimmed yield per port, and calculate gross value per port per cycle for each variety. Compare across crops and across seasons. Herb ports that look low-yield by weight may generate higher value per port than lettuce ports. The allocation that maximises total harvest weight is not necessarily the allocation that maximises total cycle value.

A port allocation decision grounded in value rather than visual bulk. For most Bangkok apartment tower operators selling to restaurants or markets, a 40 to 60 percent herb allocation by port count will outperform a lettuce-dominant configuration in gross value per cycle despite producing less total fresh weight.

Growers considering whether to add reservoir cooling for hot season

Calculate the yield gap between your documented cool season and hot season per-port averages. Multiply the per-port gap by your port count to get the fresh weight shortfall per hot season cycle. Multiply by your sale price or imputed household value per gram to get the gross value shortfall per cycle. Multiply by the number of hot season cycles per year, typically 4 to 5 for Bangkok peak heat. That is the annual value the yield gap represents. Compare it to the cost of whatever cooling intervention you are considering. If the cooling cost is lower than the annual yield gap value, the intervention improves economics. If it is higher, it does not, regardless of how much better the crops look.

A cooling decision based on the actual economics of your specific tower and market rather than on general advice to manage reservoir temperature. In Plant Mood cycle data, the yield gap value across 4 hot season cycles was sufficient to justify a small supplemental cooling device within a single hot season. For a hobby grower with no sale value, the same calculation produces a different answer.

Step 3, the seasonal split in monthly yield estimates. Almost every grower who asks how much food a tower produces wants a single number. The correct answer for Bangkok is two numbers: one for cool season and one for hot season. Growers who insist on a single annual average will plan against a figure that is wrong for half the year in opposite directions.