Q: When can I put tomato plants outside in the garden?
A: Tomato plants grow best when soils are warm and air temperatures are above 60 degrees and below 90 degrees. Traditionally, our last freeze is least likely after mid-March. Most gardeners like to get their tomato plants out earlier than this, anytime after mid-February.
Start watching weather projections, up to a few weeks ahead, around mid-February. As soon as weather projections predict warm weather for a two- to three-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.
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.
Heavy, wet soils warm slowly when temperatures are rising. Alternatively, cover these spots with clear plastic, if you must, 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.
When weather projections are positive, plant tomatoes transplants in the warm soil 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 superphosphate or a natural phosphorus source such as bone meal.
Q: What is causing my pine tree to become brown on the branches?
A: If this browning was found mostly toward the ends of the branches and not in the interior and it was also on Aleppo pine and not others, then it is most likely Aleppo pine blight disorder. This is a problem restricted to Aleppo pine and not others. The browning occurs during the winter and not the summer.
In severe cases, entire branches might die but, usually, this browning of the needles is restricted to the last foot or two on the ends of branches. With light damage to the needles, the needles will turn brown and die, but the branch supporting them remains alive.
Check if this is the case by bending the ends of the branches if you can reach them. That might be difficult in most cases because the damage is usually in the upper branches.
I like to call it a disorder rather than a disease because no disease agent or pathogens such as a fungus, bacterium or a virus has been found to cause the problem. The problem seems to be worse after hot, dry summers, and it is thought to be related to drought in some way.
According to the University of Arizona, these trees should have an adequate water supply during the heat of the summer. If branches do not die, the brown needles will drop and new needles will replace them, so make sure they get some fertilizer with the water to help support that new growth.
Q: My tangerine tree’s leaves are partially yellow and curled; the tree is in a large container. What can be done?
A: The yellowing and curling of citrus leaves can be related, or they might not have any relationship at all. There could be several reasons for both occurring, and those reasons might overlap.
Curling of citrus leaves like a cigar can be from cold weather, and it can be normal for that variety of citrus. Curling of leaves could also be related to not having enough water.
There is nothing to do about the cold weather except wait for it to warm. But use a soil moisture meter, similar to those used for houseplants, to know when to water again. Push the meter into the soil 6 to 8 inches from the plant in several locations and read the meter. Water when the needle is halfway between wet and dry.
Yellowing of citrus leaves can be from watering too often and keeping the soil continuously wet. Or it could be a mineral deficiency. And it’s possible it could be from cold temperatures and intense sunlight.
There is not much you can do about the cold temperatures and intense sunlight. The tree will improve as its health improves through proper watering and fertilizer applications to the soil and possibly to the leaves.
Yellowing from a mineral deficiency, such as iron or manganese, appears on the newest leaves at the tips of branches. Yellowing on older leaves deep inside the canopy means a regular fertilizer is needed or branches eliminated to reduce shading inside the canopy.
Apply a citrus or fruit tree fertilizer now where the soil is wet but at least 12 inches from the trunk. Substitute a tomato or rose fertilizer for citrus or fruit tree fertilizer if you have that. They will be similar. Compost does the best job. Apply compost near the base of the plant instead of mineral fertilizers and water it in.
Add your favorite iron fertilizer to the soil at the same location and at the same time. I prefer iron chelates like EDDHA.
Watch the newest growth as it emerges during the next couple of weeks and look at its color. If it’s dark green, you were successful. If this new growth bstarts yellowing, then apply liquid fertilizer, such as Miracle-Gro or similar, sprayed on the leaves. Use distilled water with the teaspoon of liquid detergent in the spray mix, not only tap water.
Q: Since we have had zero winter weather here, my grape tomatoes have not stopped producing. Can I leave them in a raised bed?
A: Tomatoes are tropical plants, so take advantage of their size. Cut them back 6 to 10 inches to encourage new growth. Fertilize and water the plants to encourage flowering and fruiting. They produce better if cut back and allowed to flower on new growth.
Use mineral fertilizers applied to the soil if you want, but I prefer compost applied in a circle around the plants 6 to 8 inches away from the stems and watered in. Another alternative is applying a liquid fertilizer sprayed on the leaves four to six weeks apart. This spray can be made from powdered all-purpose fertilizers like Miracle-Gro, Growmore, Peters or compost tea.
Q: When is it time to start fertilizing lawns again?
A: It depends on whether the lawn is fescue, only Bermuda grass or Bermuda grass overseeded in fall to maintain green winter color. Fescue lawns and overseeded Bermuda grass lawns are fertilized the same during winter months.
Fescue and overseeded Bermuda grass should have been fertilized the past Thanksgiving to maintain dark green color through winter. If this fertilizer application was missed and temperatures get cold, the lawn can turn brown when it gets very cold or just light green if it does not.
The next fertilizer application to fescue lawns would be when air temperatures enter the 60s. Fertilize Bermuda grass that was not overseeded when temperatures enter the 80s.
Established lawns require fertilizers containing high nitrogen and occasionally an application of iron for dark green color. But they will perform best if this fertilizer also contains low levels of phosphorus and moderate to high levels of potassium.
For this reason, fertilizers similar to 21-7-14 or 10-5-10 are frequently recommended for lawns. Some people use only high nitrogen fertilizer such as 21-0-0 and omit phosphorus and potassium.
I think that this is a mistake and a good lawn fertilizer should be applied at least once during the growing season. Instead, experiment and try fertilizing with only half the amount of fertilizer recommended on the bag. This is all that is usually needed if you are not bagging lawn clippings but mulching them back into the lawn using the mower.
Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.