Expert: Mike Mascio - 6/20/2006

Question
I started to do a little gardening this summer.  My sunflowers are having problems.  The leaves keep turning brown and other look as though something is eating them.  I'm not sure if this is a product of too small a pot, too much water or too little?  I have been trying to water them everyday.  It is pretty hot here now in Southern California and they are in a lot of direct sunlight right now.  I'm not sure what is eating them either or what to do about it.  

Some of my other smaller flowers are not blooming.  I did trasnplant them recently, perhaps that is why they havent bloomed yet?

Any general gardening tips for someone starting out?

What are some easy plants to start out on.

Answer
Brett, I suspect the plants are receiving inconsistent watering, especially if they're in pots. Too much watering can water log the roots, resulting in the plant being unable to draw in oxygen and nutrients. Too little causes the plant to stress.  Given how quickly pots dry out, this is a common problem.  My advice is to water the pots very deeply in the morning, and let them be for the rest of the day.  Deep watering causes the roots to reach down, where shallow watering causes them to reach for the surface.

In regard to the new transplants, this is normal.  It takes several weeks for transplanted annuals to begin blooming.  They need to acclimate to the soil.  Also, be sure to fertilize them with a fertilizer high in phosphorus and low in nitrogen.  Phosphorus promotes blooming, whereas nitrogen promotes lush foliage at the expense of blooms.

I can't say with any certainty what is eating your sunflowers without seeing the damage, but I would suspect whiteflies, aphids, or flea beetles.  Any of these can be controlled with an insecticidal soap, or with an organic pesticide such as rotenone or pyrethrum.

The best gardening tip I can give you is to amend your soil every spring with as much organic matter as possible.  These amendments include compost, aged manure, peat moss, shredded leaves, and dried grass clippings.  This will improve the tilth of the soil and provide your plants with all the nutrients and disease resistance they will need throughout the growing season.  You can also use these materials as a mulch to help retain moisture and keep down weeds.

I hope this information helps.  Please write again if I can ever be of assistance.

Regards,

Mike