Q. I am a farmer in district Khairpur, Sindh, and have a major problem as my agricultural land, locked in by sand dunes on three sides, is shrinking due to soil erosion. As a result of strong winds and cattle movement from the dunes down to fields, sand is occupying and encroaching on cultivable land. Is there any tree, shrub or herb which can be grown on sand dunes to block the wind and prevent erosion. It needs to be drought tolerant, easily available and, if possible, also work as a fence to keep cattle out of the fields.

A. Various methods of keeping the desert at bay have been tried over the years, including dense plantations of indigenous ‘Acacia’ species which withstand drought and are thorny enough to keep cattle at bay. Having said this, please note that the best results so far have been in a number of African countries where not only has the desert been stopped from encroaching agricultural land but extensive areas of desert have actually been reclaimed for agricultural use.

The system used is called ‘Hugelkultur’, which, basically, is piling up huge amounts of organic material such as dead tree trunks, branches, cut down scrubby shrubs, plant debris of all kinds, the larger pieces forming the base of the heaps — these can be as long and wide as you can erect — graduating to a final layer of earth on top. The ridges — they need to be sizeable to work on a farm scale — are then planted with climatically suitable saplings, shrubs, even food crops which, after an initial period of watering to get them settled in — this can be done using ‘mutkha’ irrigation — obtain all the moisture they need from the rotting down organic material beneath them. Hugelkultur mounds, large ones, have been proven successful over as many as 30 to 40 years. I strongly suggest that you examine the viability of this. Miniature ‘Hugelkultur’ mounds can be used on a garden scale to improve / expand growing areas and reduce water usage.

If you have the will you can cultivate even in desert-like situations; you just need to know how

Q. I am confused about how to grow sweet potatoes. Some people recommend planting the tubers; others say that they can only be grown from cuttings. Please explain this and also their growing requirements.

A. They can be grown both ways: Small tubers can be planted, on top of ridges of sandy earth, with the top one quarter, where there needs to be an ‘eye’ or visible sprouting point, exposed to the light. Large tubers should be cut into pieces, each piece having an ‘eye’ and can then also be planted the same way. As the plants grow and send out their long shoots, cuttings can be taken from these, each cutting being approximately 12 inches in length, and stuck into the soil close to a ridge top and at a distance of three feet apart. Cuttings root rapidly.

Personally, I start off pieces of large tubers in buckets / containers of slightly damp, coarse sand (not sea sand as that is saline), eyes upwards, the top part exposed and the bucket / container sealed in a plastic bag to keep humidity levels high. Without humidity and heat the tubers will not grow. Once the tubers have sprouted and sent out stems, I uncover them and, when long enough, take lots of cuttings from each plant so that I can, hopefully, get a large crop. Once established, they grow like crazy and need lots and lots of space, sunshine, sandy soil and regular watering. They send down roots, these eventually form the tubers, from each joint and crops tend to be excellent. Sweet potatoes should, in fact, be more widely grown.

End section of a garden scale ‘Hugelkultur’ mound

Q. I have tried to grow Tulsi plants in pots three or four times but they don’t last long. The last time I bought a nice, healthy plant with lots of leaves but within six months the leaves dried out. What could the problem be?

A. It sounds as if you are buying purely seasonal Sweet Basil instead of the indigenous, shrubby, perennial Tulsi variety. Next time, check that stems are woody and hard not green and soft as the latter are seasonal and die off after a few weeks / months.

Q. I live in Karachi and have some barren land — almost 100 sq. yards — which I am planning to use for a kitchen garden. The land receives sunlight throughout the day and is in the city centre well away from sea breeze so I am expecting handsome growth. The problem is that as the land has been left idle for many years, I’m afraid it will be infested with insects like slugs, ants, etc. that might hamper the growth of vegetables and fruit trees. Kindly recommend some insecticides that I could pour in before laying new soil or that I can mix with the new soil to have better results.

A. No. Absolutely not! I am totally against the use of any chemical interventions in the garden as these toxins do far more harm, to humans as well as to the environment and all forms of life which already face a hard struggle to survive the depredations of mankind. I suggest that you deal with any problems as and when, and if, they arise, and deal with them organically please. Keep your eye on this column for organic gardening advice and do ask if you need organic help.

Q. I planted Ashok in my garden last September but one has died and the other four have turned brown which I find puzzling as it thrives in my neighbourhood. What do you think might have gone wrong?

A. Incorrect soil conditions at planting time or too much / not enough water are the most common problems when starting off young trees of any kind. Planting holes must be prepared with care and a strict watering regime followed until the trees are established.

Q. Can you please share a list of fruit plants which can be grown in pots in Karachi?

A. Grape vines, passion fruit, lemons, guava, chikoo, sharifa, dwarf dates, figs, papaya, sweet melons, watermelons, pineapples and strawberries are just of the fruits you can try.

Please continue sending your gardening questions to zahrahnasir@hotmail.com. Remember to include your location. The writer will not respond directly by email. Emails with attachments will not be opened.

Published in Dawn, Sunday Magazine, April 26th, 2015

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