When to Plant Tomatoes

Q. When can I put tomato plants outside in the garden?

We all want these, right?Putting tomato plants into the garden at the right time is critical in our hot, desert climate. They don't set fruit when temperatures get above 95° F. They grow poorly at temperatures in the 60s. That "sweet spot" for tomato fruit set can disappear quickly in the hot desert climates, particularly after prolonged cool wet springs.

A. This has been a crazy Spring! Tomato plants grow best when soils are warm and air temperatures are above 60° F and below 90°. Traditionally, our last freeze is after mid-March. Most gardeners like to get their tomato plants out earlier than this, any time after mid-February, if its warm enough.

Tomato stem rot occurs on tomato plants frequently when soil temperatures are cold and tomatoes are put outside too early.

            Start watching weather projections, up to a few weeks ahead, around mid-February. As soon as weather projections predict warm weather for a 2 to 3 week period after mid-February, put transplants outside and help them to adjust from the protected greenhouse to the harsher garden environment.

             Put transplants in a location protected from strong wind and intense afternoon sunlight. They should get eight hours of sun every day to remain vigorous. Never plant them in the same spot in the garden year after year. Plant them in a different part of the garden each year to reduce disease problems.

This tomato plant stem was buried in the garden soil. New roots were supposed to grow from the buried stem. Instead, the tomatoes them died along with the plant. The transplant was put in the garden when soils were still cold and the soil did not drain water easily. Instead, the tomato transplant developed stem rot.

            Prepare the garden soil for planting while transplants acclimate. Remember, tomatoes like warm soils so garden preparation should focus on “fluffing” the soil so that it warms more quickly. Add compost to it and double dig, spade or till the soil to open it and let warm air and sunlight raise its temperature.

Hot caps and wall-o-waters are sometimes used to protect tender new transplants when air temperatures are still cold and potentially freezing. Transplants are protected from freezing temperatures but unfortunately the soil temperatures are still cold. These cold soil temperatures don't permit transplants to grow as fast as they might.

            Heavy, wet soils warm slowly when temperatures are rising. Alternatively, cover these spots with clear plastic, if you have to, to trap heat and warm it more quickly. Pin the edges of the clear plastic to the soil to keep the heat trapped under it.

A potentially better technique is to warm the soil first with clear plastic and plant tomato seed directly into trenches in the warmed soil. This can be done in the middle of winter. This was demonstrated at the University Orchard in North Las Vegas.

            When weather projections are positive, plant tomatoes transplants into warm soil along with a pre-plant fertilizer to improve rooting. If a generous application of compost was used during garden preparation, then add only a phosphorus fertilizer to the soil surrounding the transplant. This phosphorus fertilizer could be a mineral type such as triple super phosphate or a natural phosphorus source like bone meal.

If it Survives the Winter, Don't Cut Bougainvillea Back

Q. Should bougainvillea be cut back in the winter?  I have two in large pots. I want to see them grow fuller this spring and summer. Cut back or leave them?

Bougainvillea is a witty perennial shrub in semi tropical and tropical parts of the world. We can grow it in winter freezing climates because it grows back from the roots if the top part freezes. If it gets very cold, the crown or top part of the plan may die each winter this happens. In our climate we grow it as an "herbaceous perennial" like lilies and Iris. If it freezes during the winter, we cut off the top debt part and let it regrow from the roots. Otherwise, leave it alone.

A. Wait until about March 1 and see if there is any winter damage from freezing. Then decide. If there is, cut it back close to the ground and let it regrow again.

Winter freezing damage to bougainvillea. When temperatures drop just one degree below freezing, damage begins to occur on bougainvillea. When this freezing temperature remains for any length of time, more and more freezing damage occurs. It will grow back from the crown (that part of the stem and roots that connect the two) if temperatures do not get too cold for a long time.

            If there is no winter freeze damage, make this plant fuller by cutting the stems back at various heights (so it doesn’t look like a butch haircut) anywhere from a foot to foot half from the ground. For every cut you make, three new shoots will grow and increase the density of the plant.

Sugar Snaps Peas Producing Snow Peas

Q. Have had much success with sugar snap peas, but lately I’ve been planting sugar snap peas and getting snow peas instead.  Is it because the seed is old? 

Snow peas after harvest in Kenya.

A. I’m not sure the difference you are seeing between these snow peas and snap peas. Snow peas have flat pods when young and we see them frequently used in stirfry. Snap peas, or sugar snap peas as they are sometimes called, have round pods when they are young and not used conventionally in stirfry.

Kenya producer using sticks and string to trellis their snow peas.
High elevations in Kenya is a perfect cool year around climate for snow pea production.

            Snap peas, when they first emerge, are flat. As the seed inside the pod begins to enlarge the pod becomes round. If you pick snap peas too early they will look like snow peas. When harvesting snap peas, wait a little bit longer for the seed to enlarge and the pod to become round. But harvest the pods before the seed becomes mature. If you wait too long, the seed contains more starch rather than sugar and not as sweet.

Sugar snap pea seedlings in bloom and ready to climb the chicken wire.
Cold weather near Bloom time can cause problems and a lack of pea production inside the pod.

            The differences between the two are genetic so it should have nothing to do with the age of the seed. Snap peas were genetically bred from their ancestors, the English or garden pea and snow peas, to be less fibrous when they are young.

The perfect size for snow be export to Europe from Kenya.

            You also might be referring to the “strings” in the pod or how tough the pod is. If strings are a problem, harvest when very young or the pod may get tough when older. If you’re having problems with strings, remove the strings from the pods before using them and start harvesting earlier.