Dear Anne,

"I planted garlic in the same raised bed for three or four years. Now I have removed the top five or six inches of soil. Is it okay to fill it with straight composted steer manure?"

Beverley Nagy, via email

Sorry, but it's not okay. Even though the manure is composted, it's still straight manure.

Composting produces old, very gentle manure, but it will be overly rich feeding for garlic, and it will still retain lots of moisture. Garlic likes to be welldrained.

Although garlic is wonderfully pest-free, too much manure will encourage rots and fungal problems.

You need to mix the composted manure with soil, not compost.

It would be best to cover the excavation with an inch or two of composted steer manure, then borrow soil from elsewhere in your garden (or get some topsoil) and put that into your raised bed, mixing the soil and manure together.

Dear Anne,

"How come yellow flesh potatoes don't keep as long as the others?"

Mary, via email

Potatoes with yellow flesh are smaller and sweeter than larger potatoes. That may limit their storage life.

One useful way of storing potatoes is to keep small, medium, and large ones each in their own boxes. The small ones should be used first, because they shrivel fastest, then the medium potatoes, and last of all, the big ones.

Dear Anne,

"When should you cut back heathers, and can you be brutal?"

Donna Buxton, via email

No, you can't be brutal with heather because those dry, brown inner stems won't make fresh shoots.

You need to cut back only into the green parts of the stems. It's best to think of it as a haircut, rather than a hard pruning.

It can easily be done with shears in just a few quick cuts. But it does need to be done every year, otherwise the heathers get long and leggy and develop bare patches in the middle.

It's best to do it right after the flowers die.

Dear Anne,

"I have a pretty bad case of spider mites. I sprayed a soapy solution on the plant and will repot it into fresh soil and a really clean pot. I sure hope I can save my plant."

Marty Boychuck, via email

I hope a soapy spray is all you need to do. But spider mites often need more intensive treatment.

If the problem recurs or fails to clear, try spraying your plant with plain, cold water once a day for two weeks.

Be very thorough. Spray under the leaves and in all the crevices on your plant where spider mites can hide.

Cold and wetness sickens and kills spider mites, and it's hard for the more resilient ones to breed before they die, too.

In a couple of weeks, it will look as if the spider mites have vanished, but be cautious: there may still be eggs in secluded spots.

So taper off the spraying to once every two days, and then cut back to three and so on.

Because the weather is getting warmer now (spider mites love warm conditions) it would be best to spray your plant with cold water once a week, anyway, as a preventative.

Keep checking any plants in the same room as your infected one, because spider mites can spread from plant to plant.

Anne Marrison is happy to answer garden questions. Send them to amarrison@shaw.ca