Q: The desi roses in our Karachi garden are doing well but the English roses are doing poorly. Their leaves have turned yellow and there hasn’t been a single flower for months. How can we make them grow well?

A: English roses can, with a great deal of care, be successfully grown in Karachi even though the climate is far from ideal. They are unlikely, however, to flower as prolifically as desi ones and some of them only bloom for as little as six weeks during the cooler months of winter. They require, lots of sunlight, excellent drainage and top quality soil with plenty of well rotted, organic compost and a liberal dose of old, completely rotted down, organic manure worked in with, for good measure, some organic bonemeal added at the rate of one handful per rose bush every six months or so. Yellowing leaves are often a sign of bad drainage and overly wet root conditions.

Q: I got married recently and want to make my new home, in Karachi, a beautiful place. There is a small courtyard which has an underground water tank. Can I make a garden on top of the tank even though the lid is in the centre of the courtyard? If so, what depth and what kind of soil is needed?

A: I suggest that before laying down any soil, you first make some kind of solid ‘cage’ around the lid of the water tank to prevent soil particles from getting into your water supply. Bricks and cement are about the best options for this. After this and after marking out the edges of your proposed garden with more bricks or some other material, you should lay down at least six inches of sweet earth mixed with organic manure/organic compost. While this is not deep enough for you to grow trees, shrubs or deep rooted vegetables such as potatoes, it is enough soil for green leafy vegetables, tomatoes, cucumbers, beans, aubergines, etc. and for the vast majority of seasonal flowers including petunias, pansies, larkspur, sweet peas, violas, calendulas, antirrhinums, sweet Williams, poppies, etc. You can also grow herbs like coriander and dill.

Q: Is the climate of Karachi suitable for olives and, if so, then how should I go about growing them?

A: I have heard of people cultivating olives in Karachi but, in my opinion, the climate is far too humid. If you want to give them a try though, you will, unless you can find bi-sexual trees, need both male and female saplings and to prepare the soil well. Soil should be of good quality with plenty of organic matter worked in. Good drainage and lots of sunshine are also important. Planting distance between trees varies from type to type so please keep this in mind.

Q: I made about 10-15 kg compost but something is missing because my citrus and guava give only a few flowers and very little fruit and this fruit is small. The leaves of my grape vine are not healthy but the falsa is. What should I add to the compost to resolve these problems?

A: It would help if you explained what your compost is made from. Without this crucial information, I haven’t the slightest clue as to what you need to add!

Q: There is a large rooftop on my Karachi home and I want to grow fruit and vegetables there but do not know which size of pot to use. Please advise. I would also like to grow some indoor plants but the rooms do not get sunlight.

A: Please ensure that your roof is fully waterproofed before setting up your garden there, otherwise seepage may spoil the ceilings of the rooms below. The correct size of clay pots varies tremendously with what you decide to grow. A single tomato plant, for instance, does well in a 10-inch pot as long as soil/compost is rich enough. Instead of going for very heavy pots though, it is much simpler to utilise wooden fruit/vegetable crates lined with newspaper and you can grow two tomato plants in each of these or four to six lettuce or one squash plant or up to 112 bean/pea plants depending on the variety. Things like coriander and spinach are great in such crates but must be sown thinly as must spring onions. Four strawberry plants per crate is another suggestion. This is just a rough guide of course and you will need to judge it carefully as overcrowding of plants results in weak growth, disease and poor crops.

Q: I have one papaya and one coconut tree outside my house in Karachi. They are about seven years old but have not fruited even though they are healthy. They do flower but no fruit. What is the problem?

A: Lack of cross-pollination. Both of these species require the presence of male and female plants in the vicinity if they are to set fruit.

Please send your gardening queries to zahrahnasir@hotmail.com. Remember to include your location. The writer will not respond directly by e-mail. E-mails with attachments will not be opened.