Benefits of ‘feeding’ my tomatoes fish pond water

Friday August 05 2016
Tomatoes fish pond 1

Ms Tabitha Nyangaresi inspects tomatoes in her farm. She uses fish pond water rich in nitrogen, phosphorus, potassium, calcium and magnesium to water her tomatoes. PHOTO | JOSEPH SOSI | NATION MEDIA GROUP


When Tabitha Nyangaresi, 40, realised that growing tea was no longer viable after close to 20 years of dismal returns, she turned to tomato farming.

“I knew time was ripe for change when I started using my unused fish pond water to water my crops rather than spending most of my time plucking tea that has been paying poorly for decades yet a small potato garden surpassed its earnings in a short period,” she tells Seeds of Gold at her farm in Bobasi, Kisii County.

She sought experts’ help in putting up an underground water reservoir tank which can hold up to 48,000 litres and bought an additional three 6,000-litre tank that captures every drizzle that lands on her house roof.

Rain water from her roof flows through the eaves trough to the underground reservoir from which it is channelled to her ponds by gravity.

The greenhouse gutters channel all the water captured from their polythene roofs into the fresh water reservoir supplying her 20,000 four-month old fish with clean water fitted with a powered oxygen supply machine she purchased at Sh15,000.

Remains of feeds and excretes form settle able faecal fish waste in the pond rendering the water rich in manure.


On a good harvest from her two greenhouses, Tabitha makes up to Sh6,000 a day, selling  tomatoes to vendors who frequent her farm daily from the nearby markets in Nyamache, Mogonga, Nayacheki, Igare, Daraja in Kisii town and direct to consumers in the area including schools, hospitals and eateries at nearby shopping centres.

Tabitha says she researched on the internet viable tomato varieties in Kenya and chose to grow the hybrid Anna F1 variety which she found out matures faster and has higher produce.


“I spent time on the internet and chose the Anna F1 variety which performs best under greenhouse and is resistant to common tomato diseases. The fruits do not go bad easily after harvesting,” said Tabitha.

Tabitha says in November last year, she opted to invest Sh40,000 on a rainwater harvesting plan after she learnt the idea from a friend in Athi River.

Mr Felix Opinya, an expert in aquaculture at Egerton University, says fresh fish manure is similar in chemical orientation to other livestock manure and should be used as an agricultural fertiliser instead of using inorganic fertilisers that are not only expensive, but also harmful to living organisms.

(Read also: My fish and crops grow in the same pond)

“Water in a fish pond has advantageous amounts of nitrogen, phosphorus, potassium, calcium and magnesium that can be useful to a farmer using it in crop production,” says Mr Opinya.

Tabitha has contracted three people who assist her in the maintenance of the farm as crop caregivers.

She is glad for the fact that she does not incur transportation costs that would have eaten into her profits given the terrain of the area makes it largely inaccessible whenever it rains.

“I do not have to worry about how to reach the market any more because my customers place their orders in good time and ferry tomatoes on their own to the market,” says Tabitha who puts her average earnings a week at Sh40,000.

She now intends to expand her water storage to a capacity of 100,000 litres. She has also set her sights on dairy farming.


She is putting up a zero grazing dairy cattle unit with a bio-gas generating system to get reliable power and cut costs.

“Power outages occasionally last for more than 24 hours and this has been a worrying recurrent trend that I am exploring alternative sources of energy to act as backup and reduce my expenditure on electricity,” says Tabitha.

Her tomato productivity has grown over the last two months and she attributes it to the use of the manure rich water, saying she could be instead spending over Sh10, 000 monthly on buying fertiliser for her tomatoes and other crops.

“Using the water from the ponds after undergoing filtration gives me more savings from what I would have spent on inputs as my tomatoes, capsicum, kale and the other crops are supplied with this water containing free manure,” reveals Tabitha.

One of the key challenges is the spending on pesticides.

In June at the beginning of her harvest, she made a profit of Sh80,000.