Herbs not growing well indoors in pots - Knowledgebase Question

Dekalb, IL (Zone 5A)
Question by joydavis99
May 12, 2005
I bought several herb seeds this spring(parsley,thyme,dill,oregano,basil,lavender, rosemary,spearmint,and chives)with the hope of growing them indoors in 4 to 6-inch clay and plastic pots. I planted a couple of seeds in each pot placed them in a west facing window and water only when the soil feels and looks dry on the surface. The parsley,chives,oregano,tyhme, and basil have germinated and are bearing lttle seedlings. The spearmint,lavender,and rosemary have not germinated to date. I looked at the surface of the soil and I noticed very tiny white bugs crawling around on the soil in the spearmint and lavender pots. What might these bugs be? And what should I do to alleviate this problem? Also, my thyme and oregano seedlings are growing very tall,weak, and spindly. What am I doing wrong? Should I have started the seeds in a seed starting mix? Should I have sterilized the pots? Is it posssible to grow herbs indoors without the aid of a grow light? Can I place the pots under a grow light after the seedlings have sprouted to help them grow strong and bushy, or is it too late? I was told that placing a fan near the pots will help the seedlings grow stronger. Is this accurate? Also, can you suggest a very good book,guide,call center, or web site that gives step-by-step information on growing the herbs mentioned above from seed indoors, for the complete novice.
Thank you, and sorry for the many questions.


Answer from NGA
May 12, 2005


It is difficult to grow good quality herbs indoors on a window sill year round. Tall and weak seedlings generally indicate a lack of light and/or overfeeding. A bright room with a southern window would be best, the western exposure is the second choice. For supplemental light you could try growing them under an ordinary fluorescent light, keep the bulbs within an inch or two of the foliage. This will keep them healthy if it is used to supplement sunlight through a window.

The fan is sometimes used to help crowded seedlings grow stockier and to provide good air circulation and prevent damping off, but it isn't a necessity if they are in a room where people walk by occasionally for example. You can run your hand over the top of the plants and brush them off a bit once or twice a day and in my experience this seems to cause a similar reaction.

If you trim them back periodically to harvest for fresh use this will help keep them denser. Also, do not overfertilize them. If you used a soil based mix, you may not need to fertilize for several months as herbs grow better in lean soil. If you used a soilless mix then you may need to fertilize at about a quarter the label rate every other week or so while they are actively growing.

I am not sure what the little white bugs are, they may be fungus gnat larvae. If you used a soil based mix it could be any number of things that came in with the soil. Without knowing what they are it is difficult to tell you what to do exactly. The first step would be to make sure you are not overwatering. Allow the surface to dry and water when the soil feels dry when you dig into it with your finger. You could also place a thin layer of sand or fine gravel on the surface, this would prevent the adult fungus gnats from breeding there and stop the problem in a week or two if that is the culprit.

You have done really well to have all those different seeds germinate. I should point out that these are annuals and will need to be replanted from time to time as the older plants lose vigor. The perennials, lavender and rosemary are more often started from tip cuttings than seed, mints are usually started by division, so that might be something to consider.

Much of gardening is trial and error and finding out what works for you in the growing conditions you have. Some seed starting and herb growing instructions you might find interesting:


There are many more herb growing articles at

Enjoy your project!

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