Trouble With Growing Basil

Question From Chip

Hope you’re doing well.  Even with the earthworm castings and moisture retention pellets (and Miracle Gro) we still haven’t had any luck with the basil.  I’m thinking we’re just doomed, but we may toy around with the irrigation some more before throwing in the towel.

The question today is we’d like to install one of those living succulent wall hangings on the side of the casita pictured here.  The problem is it’s on the south wall, so it would get minimal daylight/direct sun.  Do you think it would survive with only filtered sunlight?

Thanks for any quick thoughts.

Basil photo

Answer From Pat

First it’s highly unlikely you can grow basil well at this time of year in your climate zone without some kind of protection at night, unless it’s a perennial basil, such as African blue basil (Ocimum kilimandscharicum x basilicum ‘Dark Opal’, which has a somewhat different flavor and thus more often grown as an ornamental. There was a craze for this plant 10 or 15 years ago and now fewer gardeners grow it. The reason you could most likely grow it is because it has deeper roots than the common green basil (Ocimum basilicum.)

I think the problem with growing basil in your raised beds might be that your beds are filled with potting soil or a commercial “top soil” that drains too rapidly and thus dries out too fast. Basil needs moist soil in order to survive. I have suffered with this condition in my own raised bed which is three feet tall, 8 feet long and 4 feet wide. I could not keep the soil moist and thus when I went on a trip in early summer a couple of years ago and was not home to give my tomatoes supplemental irrigation, even daily if necessary, my gardener failed to notice what was happening and under-watered my tomatoes so when I returned home they had all shriveled up and died from insufficient irrigation.

As you know, for the last 2 or 3 years I have been following the advice of Steve Gotto who said to get rid of pests and diseases in raised beds so one can grow tomatoes without rotation the way to go is to spread soil amendments on top of the potting soil prior to each planting season, spring and fall, and contrary to conventional wisdom NOT dig it in. I decided to use his method to improve water-retention and have been doing this twice a year for 2 years now, spring and fall and have finally cured the problem with overly fast drainage and soil drying too soon. No one would believe the amount of soil amendments I have added to my 8 X 4 foot raised bed each time I have done this, but at least 6 bags of some kind of special manure I found at Dixieline, plus three bags or four bags of Eco-Compost made from green waste, sometimes 2 bags of chicken manure and several bags of earthworm castings until this year when I could not find them. Manure provides too much nitrogen for growing any kind of legume like peas and beans, but now at last the soil stays moist and my cole crops have been surviving on twice-per-week irrigation. My experience is that earthworm castings and cow manure are the best for correcting drainage problems but cow manure adds so much nitrogen it is too much for some crops. Earthworm castings do not add enough nitrogen to be considered a fertilizer but they kill pests and also improve water retention. You don’t want to grow legumes or any root vegetable with this much manure, but tomatoes do wonderfully well if you add other nutrients they need. Once manure is leached out it’s fine for a leafy green such as basil.

Another way to correct drainage that is too fast is to apply an organic wetting agent such as Yucca schidigera. A third and wonderfully effective method is to forgo growing vegetables one season and grow a cover crop instead. My favorite cool-season cover crop is Crimson clover (Trifolium incarnartum). I even found a package of seeds at a local nursery the other day. Plant from seeds in fall, and dig into the ground the following spring. Best time for most nitrogen is just before flowering but I always let my plants flower since the flowers are so pretty. Then dig into the ground, which means turn the plants upside down with a spade and make sure roots are fully covered with soil. Keep wet. They rot in a couple of weeks and then you can plant. Your soil will be black and wonderfully fertile and hold water much better.

A final thought: Raw, ground-up or chopped wood that is found in many potting soils and top soil mixes, that has been added to soil without adding sufficient nitrogen will rob the soil in order to rot and thus will kill plants.

 Have you thought of filling large pots with a potting mix containing a wetting agent and growing your basil in those?

Re: Your second question:  I have seen many succulent walls and succulent wreaths, hanging in shade with bright reflected light such as south-facing shade in summer and no problem. In winter south-facing wall is in full sun, unless it is under a very deep overhang or the sunlight is cut off by walls on the north and east. Thus south-facing shade should be a perfect exposure for succulents.

Additionally in a restaurants in Hollywood I have seen several walls of succulents that are not well lit. Succulents will survive this way for a long time. When they get too leggy, one can cut the plants off, let them callous overnight and replant by making a hole with a chopstick and sticking the shortened stems back into the arrangement while securing, if necessary, with small-size landscaping pins made of bent wire available at florist-supply stores such as Michael’s.

Fertilize occasionally by spraying with a small hand sprayer filled with a balanced, house fertilizer or with de-odorized fish emulsion diluted according to package directions.

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