Growing Herbs Indoors
Answered by: Inge Poot
Question from: Phillip Stands
Posted on: October 15, 2001

I am planning to grow some common herbs indoors over the winter and needed some info.

1. I was planning to start some spearmint and the question I had regarding this was the root size, how deep does it develop? What circumference is comfortable? Can it be grown from seed? I know some mints are reproduced through rizhomes, and I was wondering how spearming reproduced.

In the garden mints produce a root system that may go down as deep as 30 centimeters (a foot) and have a similar circumference. However, pot grown plants will have much shorter and narrower root system. A 15 centimeter (6 inch) standard pot will produce a nice sturdy plant as long as you keep it moist and give it sufficient light, plus the occasional fertilizer.

2. What are some commond signs that rosemary is potbound?

Most plants start growing roots out the bottom of the pot when they become potbound and rosemary will do that too. Repot rosemary into fresh soil once a year even if it is not potbound, because the top of the soil tends to get crusted with algae and then it is hard to see if the soil is getting dry. Letting rosemary dry out completely even once is fatal even though it takes a while for the death of the plant to become evident.

3. My root question also applies to lavender.

The same answer as for the rosemary applies, but with lavender you must be very sure that the plant has excellent drainage but does not dry out completely. However if it does happen it will not be always be fatal! Make sure the plant has good light, otherwise it will get very spindly and weak over the winter.

4. What tips would you recommend for growing St.Johnswort?

It likes excellent drainage, good light and regular watering. It may be difficult to grow out of doors if you are not within 200 miles of a large body of water and between the 42 and 47th parallel on the earth. It survived really well out of doors in full sun in my sandy but manured soil without watering, even though we had a two months long drought this summer.

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