Q. I have a small garden in Karachi so I grow most of my plants in pots. The plants are unhealthy as when I water them they do not drink the water. It stays lying on top of the soil and the few plants that manage to flower have very small blooms. Please explain how to improve the health of my plants.A. Your plants are suffering from being over-watered. The soil they are in must be completely water-logged which is why, probably combined with inadequate or nonexistent drainage, the water is stagnating on top of the soil. Please make a new start. Take the plants, at least those that are still in a reasonable condition, out of their pots, leaving the soil intact around their roots, lay them on their sides in the sunshine and let the soil dry out a bit before removing at least half of it without, that is, damaging the tender roots.

Meanwhile clean out the pots, make sure that drainage holes in the base are free of obstruction, lay broken pieces of pot, at angles, over the drainage holes to keep them clear of soil. Half fill the pots with a new mix of 50pc sweet earth, 25pc river sand and 25pc organic compost and carefully insert your surviving plants, pot by pot. Water the plants very lightly to settle them in and then, this is of prime importance, only water when the soil is dry to a depth of one to two inches on top. You can easily check this by sticking a finger in. Water lightly in future and only when needed.

The watering requirements vary from species to species but, generally speaking, at this time of the year, watering twice — maximum three times — a week is quite sufficient. Over-watering kills off more plants than anything else so please be careful about this, and drainage, in future.

Q. Our lemon tree is almost eight years old and has produced a huge quantity of lemons over the last few years. Now, however, the leaves have turned pale and have started to fall and some of its branches have dried out. What is the problem and how to deal with it? We reside in Karachi.

A. There are two distinct possibilities here: 1) Bad drainage has caused disease in the tree roots which, if so, will be rotting away in the ground or 2) The tree is starved of essential minerals and nutrients such as iron and potash.

I suggest that you check for root rot first and, if it is present then you can try and save the tree by improving drainage although, depending on the exact type of infection, it may be too late for this. If this is the case, remove the tree, improve drainage but do not plant another lemon in the same place as disease spores can remain present in the soil for years.

If it is the second scenario, treat the tree to a regular feed of liquid, organic fertiliser of a kind that is high in the minerals mentioned: You can make your own liquid fertiliser by soaking some iron nails (not stainless steel) in a bucket of water for two to three weeks or until the water turns rusty when the nails can be removed and wood ash (natural potash) can be stirred in along with some ‘compost tea’ or something similar. This can be fed to the tree at weekly intervals round the year so make sure that you use a large bucket or a number of buckets in rotation.

Q. I have a chikoo tree in my garden in Lahore. It has attained a height of over 10 feet but does not flower or fruit. Could you please guide me as to the probable reason for this?

A. Chikoo trees grown directly from seed do not, as a rule, bear fruit. Nursery bought chikoo saplings are always grafted.

Q. The branches of my mango tree are drying out and a gluey, yellowish liquid is coming out in different places. Please help me with this problem.

A. This sounds like ‘gummosis’ which can look very alarming but it does not affect the overall health of the tree. But as you mention dried out branches then perhaps you have a different problem. Please send more details.

Q. I am trying to grow a money plant in the porch of my apartment. It has grown in length but most leaves have become dark brown and stiff. There are a few other small seedlings growing in the soil to which I have added some tea. Is the tea good for them and why have the leaves become brown? Should I let the money plant grow in any direction or should I tie the stem upwards? I water the plant four times a week but how do I know whether it is sufficient or not? The porch faces north. I am a student of class 8 in Rawalpindi.

A. Your plant, in its north facing position, has suffered badly over the winter and its leaves have been killed by cold winds. It should pick up in warmer weather but will need moving into a sheltered spot or be given protection next winter. Black, sugarless tea is good for plants, weeds are not. You can train the plant upwards or let it do its own thing. Watering four times a week is far too much unless the weather is scorching hot. Reduce water to twice a week and water only lightly. Feed it with liquid, organic fertiliser every two weeks and it should thrive.

Q. Can dwarf oranges be grown on a roof top in Karachi? If so, will they fruit and how do I ensure a heavy crop?

A. Not recommended in Karachi. Try dwarf lemons instead. Providing soil rich in organic material and watering lightly but often will help. The plants may need protection from wind if the rooftop is very exposed and definitely if it is close to the sea.

Please continue sending 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.