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The Plant Lady: Tomatoes are everyone’s favorite. Here’s how to make sure they’re amazing

How to grow 2-pound tomatoes

Pete Frichette of Sacramento shows how he grows 2-pound Aussie heirloom tomatoes with less water during the California drought.
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Pete Frichette of Sacramento shows how he grows 2-pound Aussie heirloom tomatoes with less water during the California drought.

Tomato fever is kicking in now for most people. Remember though, it is best to wait until night temperatures stabilize at 50 degrees or higher before planting. Lower soil temperatures can reduce root set, so patience is key.

Tomatoes are one of the few plants where burying the stem is actually beneficial. For most plants, especially woody ones, burying stems can result in rot. However, tomatoes have the ability to produce adventitious roots along their stems, resulting in attainment of a bigger root system faster than occurs when just planting the rootball. There is not an exact rule of how much to bury. Leave at least two sets of leaves above ground and remove the leaves along the portion of stem you plan on burying.

I often get asked how much to fertilize tomatoes. If and when I do, it is early in the planting season and just once or twice. I am a fervent believer that amended soils provide all macro and micronutrients a plant requires for a season. If you do fertilize, be aware that too much nitrogen can prevent fruit set. The plant is tricked into producing more green material and not flowers and fruit. If fertilizing use a balanced fertilizer such as a 10-10-10. I amend with compost, chicken manure and sometimes alfalfa pellets.

Mulch

I am a big fan of mulching almost all plants, especially my vegetables. Major reasons are that it buffers the soil from direct sun, insulates the soil and helps even out moisture.

Blossom end rot – the rotting of the blossom side of a tomato – is due to a lack of calcium moving to the ripening fruit. The culprit is not lack of calcium in the soil, but the plant not being able to utilize the calcium due to soil moisture/temperature levels.

Early in the season, temperatures and moisture levels are erratic. Mulch helps to stabilize this situation. Additionally, compost migrates into the soil adding nutrients, entices earthworms to move closer to the top of the soil and prevents weeds. Compost and wood chips are two options for mulch; apply at least 3 inches.

Yellowing

Lower leaves yellowing is normal as the plant grows and ages. Nitrogen will move out of older growth and to newer growth as needed.

However, watch for yellowing that occurs all over a plant. This can be a sign of overwatering resulting in leaching of nitrogen. Also, yellowing and dying off of individual stems can indicate a pathogen – specifically Fusarium or Verticillium. Fusarium will discolor the inside of the stems (appearing brown). Once a plant has been infected with either one, it is a matter of time before it succumbs.

Luckily these diseases do not move from plant to plant, but are introduced through the soil. They can remain in soil for multiple seasons, so best to replace soil or rotate crops if you suspect the pathogens. Look for resistant varieties as well – they will be marked with a “VF” on the label.

Lack of fruit set

Lack of fruit can be frustrating. One potential reason is a lack of pollinators. This can be a problem if you or your neighbors are using broad spectrum pesticides.

Tomatoes are self-pollinating, meaning the pollen from the flower only needs to come in contact with the female (stigma) part of the flower. As such, tomatoes can easily be pollinated by shaking or using a hand pollinator (sold at nurseries). Heirlooms are great, but keep in mind many are not known for their abundant production – particularly large fruiting varieties, where it is definitely size of fruit over quantity.

I recommend planting a high-yield tomato – such as Celebrity or Early Girl – along with your heirlooms. Finally, note that over-fertilizing with nitrogen and less than six hours of sun per day can also prevent flowering/fruiting.

Pests

For the most part, tomatoes are pretty tolerant of any mild insect infestation. Having said that, Tomato hornworms can decimate a plant overnight.

If you notice any chewing of leaves, then it is time to hunt. Hand remove the hornworms and/or apply Bacillus thuringiensis, a natural bacteria safe to use on edibles. Aphids, thrips and whiteflies can also attack your tomatoes. A simple spray with the garden hose or soap spray can eliminate them.

Mites are a bit different. You may not notice mites until they have discolored your tomatoes or set webbing. Russet mites will cause a reddish hue to your tomato leaves but no webbing. The good news is sulfur dust does a great job of eliminating them. Spot mite can be controlled by repeated hose blasts.

Root knot nematodes get their own section – not because they are more common than other issues, but because it is harder to diagnose them during the growing season as they mimic many of the aforementioned symptoms. Nematodes are microscopic worms that invade root tissue causing swelling and nodules on the roots. This induces a decrease in water and nutrient uptake, resulting in a yellow, stunted, unproductive plant.

When you remove your plants at the end of the season, the nodules will be very evident. If in a pot, remove that soil (get it off your property). If in the native ground there are some measures that can be taken, such as solar sterilizing the soil and using resistant tomato varieties in the future (which are indicated by an “N” on the label).

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