Primetime Newspapers
By Calvin R. Finch, PhD, SAWS Water Resources Director,
and Horticulturist
Week of January 16, 2006
“Mid Winter is the Time for Sweet Peas, Onions, and Potatoes” 

            Sweet peas are difficult to grow in San Antonio but if the weather cooperates, they are worth it.  The colors are spectacular and the fragrance is only matched by stocks in the winter garden.  Sweet peas are also excellent cut flowers.  The best sweet peas are the old fashioned vining selections.  Grow them on a trellis for the best display. 

           

            For a trellis there are several options.  You can build a structure with lathe or wire on a frame four to eight feet wide and at least four feet high.  They can be free-standing or part of a fence.  One of the easiest trellises to use is a tomato cage.  They are especially suitable if they are cages constructed from concrete reinforcing wire that are five feet tall.

 

            The thing that makes sweet peas tough to grow in San Antonio is that they are ruined by both hot weather and cold weather.  A few days over 80° F and they decline and they also die in a heavy freeze.  Plant them now by seed and then every two weeks until you get a good stand of plants or when February 15 arrives.  If they haven’t germinated and are prospering by March 1, it will be too hot.  Your favorite nursery will have some of the old fashioned vines in its seed rack.  They make great cut flowers.  The fragrance is very pleasing and the colors are intense.  Make sure you mulch the young plants and keep them well watered.

 

            Later this month plant onions and potatoes.  Onion plants are available at area nurseries.  Plant them in rows after you apply one cup of slow release lawn fertilizer per eight feet of row.  Plant them close together (every two inches) so you can harvest green onions in February through April.  The last onions left in the row should have at least four inches between plants so they can form full size bulbs.  The bulbs are ready when the tops fall over, usually at the end of May.  The bulbs last until Thanksgiving, most summers if you store them on a picnic table or bench in the shade.  They store even better in a mesh sack in an air conditioned room, but the inevitable rotten onion will drive you out of the house.  They stink when they rot!  Fertilize onions every month with slow release lawn fertilizer.

 

I also like to plant my potatoes in late January or early February.  The yield is not huge but there is nothing better than boiling up a mess of your own new potatoes.  Dig trenches 12 inches deep and place a piece of potato every two feet.  Cover with three or four inches of soil.  Fill in the trench as the potato plants emerge.  If you have the soil you can also hill up around the plants.  The potatoes are produced on the stems in the trench and hills.

 

You can fertilize the potatoes at planting but they do not need supplemental fertilization.  Potatoes rot if they get excessive water.  Potatoes grown in San Antonio do not store well so harvest and use them as they are ready.  Begin to harvest the tubers when the bloom appears and dig them all up when the plants die.  Pick potato bugs off the plants by hand or use carbaryl (Sevin) to kill them. 

 

            There is nothing better than a mess of new potatoes boiled in their skins and then buttered generously and decorated with a few parsley sprigs (also picked from your own garden).