Keith Stangler: Reuse flat but not the soil

We started many of our own plants indoors last year from seed. We used a good, sterile seed-starting mix and it all worked pretty well. We still have some of the plastic flats and soil mix from last year which is still in the flats that has been stored in the garage. Can we reuse the flats and soil for this year's seed?

The plastic flats can be used again but must be thoroughly cleaned first. Put them in hot, soapy water and scrub them thoroughly — they should look just like new when you are finished. The soil mix should not be used for starting seeds again but can be used for houseplants, outdoor containers, or mixed into flower or vegetable beds.

For the past two years, I have accumulated two large compost piles that are ready to use now. I plan to put a thin layer over my lawn and the rest in my flowerbeds this spring. I am concerned about the seeds that might be in the compost. Do you think they will create a problem for me?

The process of composting usually creates temperatures of about 150 degrees inside the pile. This high temperature kills most weed seeds.

I have read that there are two different kinds of pansies. True or false?


There are both grandiflora and multiflora types. Grandifloras have larger flowers while the multifloras have more, but smaller flowers. Both can be very showy.

A friend of mine starts all of her herbs indoors during winter and then sets the started plants outside in the garden in containers in May and June. Can't I just plant the seeds outdoors in the garden?

Direct seeding is not very effective with herbs. Most require a growing season too long for this to work well. Some, like yarrow and savory, have such tiny, fine seeds that indoor seeding is much easier to manage. If starting seeds indoors is inconvenient for you, purchase started plants at your favorite garden center.

We planted a lot of spring bulbs and iris rhizomes last fall. Should these be fertilized this spring? We did not fertilize them at all when we planted.

Both bulbs and iris respond well to fertilizer. As soon as you see new growth each spring, fertilize these plants with a good general purpose fertilizer like 5-10-5 or use a specially prepared bulb food.

We tend to plant vegetable seeds real thick in the garden and after they are all up, thin them to proper spacing. They seem to come up better and make it easier to find the row for that first hoeing. Is that a waste of good seed or something we should continue?

The practice is obviously working well for you and you have sighted some very good reasons why. Many seed packets contain more seeds than a family can really use anyhow, so I would say to keep up the good work. But, do not forget to thin the plants as soon as they are up good or harvest could be very disappointing for you.

Keith Stangler of Byron is a horticulturist. If you have a question for him, e-mail it to

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