Thanks for your offer of a tip. One thing you may help with is my citrus(think it is a grapefruit) tree. Had a lot of bugs and 'lumps' in the smaller  branches. The long & short is that I cut off all the foliage and other branches leaving only the (healthy) mature stem and branches. Some new buds are now sprouting. Should I feed them anything? The soil is poor. More like a clay. Does not get too much sun in the winter.

sounds like you had paper wasp, you have done the right thing, just give it a good feed of liquid fertilizer, Citrus trees loike to be infull sun

I want to know what to do about stink bugs on my orange tree.  The tree has gone (since we moved in and don't spray it) from a happy fruit producing being to totally fruitless!

spray them with 25% vinegar and 75% water with a dash of liquid soap and give the poor tree a good feed of animal manure liquid fertilizer, just poor it around the drip line

I get lots of little zucchinis but they do not grow and soon rot.

Zucchinis and pumpkins have to be cross-pollinated to grow. Take a male flower, the one with pollen and no fruit, and carefully brush the pollen onto the pistil at the base of inside the female flower. A pollen-laden male flower will fertilize more than one female. If you think it might rain or you overhead water, it helps to close up the flower after you have pollinated it.

My pot of basil grew tall and thin and then died. Why?

Most basil varieties can grow into really large bushes. So if you grow them in a pot it has to be a big one with good fertile soil. Basil also needs plenty of sunshine and water (but good drainage as sitting in water will eventually make the leaves go black and drop off.) Most basil plants are annuals. When it is young, snip off any flowers that start to form. As it ages leave some so you can collect seed for your next crop.

Is it OK to use fresh chook manure?

As a general rule, No. It is too strong. If it is from your own hens or from a source you know to be antibiotic and hormone free, then you may dilute it with water to the colour of very weak tea and use it. Otherwise mix it, sprinkling it through, your compost heap.

I grew my first lot of potatoes and many of the bigger ones were hollow inside. What happened?

This is because when they were growing their water supply must have been irregular. Potatoes like their soil to be moist and stable. So never let the soil dry out and make sure that if, for example, you have really heavy rain, the excess can drain away.

I don't have any worms in my garden. How do I introduce worms?

You don't have to bring in worms. If your soil is poor/dry then fork in some compost and then put down a layer of mulch and keep moist. Keep mulched. The worms will arrive in due course. When we moved here our soil was very sandy. But in no time we were having to apologise to the worms for disturbing them when we planted out seedlings.

I'm getting a lot of grubs and insects in my compost heap. Is this alright?

Your compost heap is probably not heating up, not decomposing. It needs to be fairly compact and not dry in any part. Try reforming it, and put fresh grass cuttings, soft prunings and animal manures in between layers of the original materials. Then give it a really good soak and either cover it up or keep adding to it. Try to keep the heap as high as it is wide and with no pockets of unfilled spaces.

You recommend to grow comfrey to use as a fertilizer but someone told me that it is a very invasive plant. Is this so?

Comfrey will grow from small pieces of root so if you remove a plant you could leave bits behind that will grow. But the plant itself will not invade the rest of your garden (like mint does through roots that spread.) The clump will get bigger but will stay in the one place. Just use leaves for fertilizer.