Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request: Why no tomatoes? Starting to get lots of flowers but almost NO tomatoes? Plants look very healthy. Live in central County

MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about no fruit but lots of flowers on your tomato plants

There could be several reasons for lack of fruiting in tomatoes:
-- Night temperatures too low, below 55ºF (12.8ºC);
-- Daytime temperatures too high, above 90ºF (32.2ºC).
The plants will produce when temperatures become favorable. Note, though, that heirloom tomatoes can be fussier about temperatures than most hybrid tomatoes and in some areas can wait until late summer or early fall to start setting fruit.
-- Excess nitrogen fertilizer. Lots of healthy green leaves and stem growth, but few flowers or fruit.
-- Too much shade – you need a minimum of six hours of sun to produce fruit.
-- Lack of pollination. While tomatoes are self-fertile, the conditions mentioned above will inhibit pollination.
-- Plants set out too early in spring. -- We recommend planting tomato seedlings the first of May; often earlier planting of seedlings will be inhibited by cold temps and they will just “sulk”; consistent warmer weather and nights should get them growing

Recommendations:
-- Choose varieties adapted to your climate zone,
-- Plant tomatoes in full sun,
-- Keep soil evenly moist, 
-- Avoid excessive nitrogen fertilizer, and
-- Tapping on blossom stems 3 times a week at midday when flowers are open may improve pollination and help set fruit.
 
Here is a comprehensive UC link about tomato culture, pests, diseases, and environmental disorders: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/tomato.html
 
We hope this information helps! Let us know if you have any additional questions.

Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone:  (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/  MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/)

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request: Do you have recommendations on tomato cages? I bought the heavier gauge tapered cylinder ones at the “big box store”. Even though they are sturdy the bigger heavier tomato plants tipped them to the side. I then built wood ones out of 2 x 2 and 1 x 2 and they were sturdy but rotted after two summers in well-watered soil. Ideas?

MGCC Help Desk Response: Thank you for contacting the UC Master Gardener program with your question about tomato cages.

Those big indeterminate varieties can get quite unwieldy! If the wire cages you have are big enough, you could try tying them to a (e.g. re-bar) stake firmly anchored in the ground to stop them falling over.

But, but if you want something more hefty, my favorite (and what we use at the Master Gardener demonstration garden) are made of concrete reinforcing mesh. This generally comes in a 5 ft. width, tall enough to roll up into a cage. You can buy a roll at most home improvement stores - sometimes you can find flat pieces, but I have not found any that are big enough to make the cage. As for how to make them, a Google search will come up with a number of sites giving clear instructions. I use heavy duty zip ties with a one square overlap to connect mine - that way I can cut the ties and store them flat at the end of the season.

Buying a 50 or 100 ft roll of this stuff seems like a lot, but if you grow a number of tomato plants it is quite inexpensive, and I have found the wire also very useful for trellises, etc. It is not the easiest material to work with, you need a heavy duty wire (or bolt) cutter and some space to roll it out and wrestle into shape! Maybe a joint purchase and construction project with neighbors and/or relatives might make this a more feasible project. If you only grow a few plants, an online search for 'heavy duty tomato cages' will bring up some other options.

One other tip - I have found that tying the cage to a re-bar stake prevents any toppling over, and these stakes last for many years.

I hope this helps, and good luck with your garden, and tomato growing!

Help Desk of the UC Master Gardener Program of Contra Costa County (SMW)

click here for details on the Great Tomato Plant Sale

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer our gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone:  (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/  MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/)

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County 

Client's Request (from telephone conversation):  Help!... I'm growing tomatoes in an enclosed courtyard. I'm now seeing tomatoes disappearing and some with gnawed portions of low hanging tomatoes. I've heard a lot about voles being quite prevalent this year. Do you think it is voles? Other than the disappearing tomatoes and gnawing, I haven't really seen signs of other “animals”.

MGCC Help Desk Response: Thank you for calling the UC Master Gardener Program Help Desk this morning with your question about your disappearing tomatoes.

Although you suspect voles in your courtyard, they are an unlikely culprit in this case because the garden area you described is entirely enclosed except for the roof area, which is open to the sky. In order to enter the garden area, an animal would need to climb, and voles are poor climbers. It is true that Contra Costa County has had an explosion in the vole population this year, but nevertheless it does not seem likely that they are your culprit.

On the other hand, rats are excellent climbers and though somewhat larger, look similar to voles. (Voles can be up to 8 inches long, including the tail, and they have a short tail. While rats are much larger than the common house mouse or meadow vole, a young rat is occasionally confused with a mouse. In general, very young rats have large heads and feet in proportion to their bodies, whereas those of adult mice are proportionately much smaller).

Rats are very common in most neighborhoods. There are two common types of rats: Norway rats (Rattus norvegicus) and roof rats (Rattus rattus). Both are active at night. Either one could be eating your tomatoes, although roof rats are the more likely culprit, since they favor fruits. Rats could be entering your courtyard garden from the roof top opening, or they could already be resident in your attic or building.

Reducing the rat population should be the first step in protecting your tomatoes. Sanitation and making your courtyard less hospitable to rats, can go a long way to reducing the population. If you have bird feeders, either remove them or clean under them daily and take them inside at night. Also, talk with your neighbors about reducing rat habitat, as this is usually a neighborhood-wide problem. (Rat habitat outside of your courtyard might include woodpiles, moist areas in and around gardens, and dense vegetation such as ivy.)

Trapping can also work to reduce the population, but it is difficult to make a permanent dent in the population through trapping alone. Snap traps are the best traps to use as long as you can place them where other animals (squirrels, opossums, and birds as well as your dog or neighbors' cats) can't get to them. For roof rats, the traps should be placed in off-the-ground locations such as branches or fences.

If you use traps, check them frequently for dead rats. Do not touch rodents with your bare hands. Make sure you wash your hands thoroughly after handling traps. Dispose of dead rats by burying them or by placing them in a sealed plastic bag and putting them in the trash.

In the meantime, physical barriers can be used to protect your tomato plants directly. One approach is to erect a 1 foot tall barrier using metal roof flashing (obtainable at the hardware store) all the way around the planting bed. Rats are unable to gain traction on the slippery surface. Alternatively, you could build a small-mesh (no larger than 1/4 inch holes) enclosure around the bed or around each plant. Since rats, especially roof rats, are excellent climbers, the wire mesh enclosure would need to go up the sides and across the top of the plants.

We do not recommend use of rat poisons, especially out of doors, due to risk of harm to wildlife and pets either by eating the poison directly and/or indirectly in eating the rat.

For more information on rat identification and management, see: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74106.html

And for information on voles see: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7439.html

Hope this information helps you eliminate those disappearing tomatoes. From the inquiries Master Gardeners have received about rats this year you are not alone.

Please let us know if you have further questions.

Good luck with your tomatoes!

Help Desk of the UC Master Gardener Program of Contra Costa County (MCW)
Please Join us at "Fall for Plants" on September 9 for the workshops and the plant sale, Registration is optional, but it'll get you a free plant from the sale. Hope to see you there.

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/).

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client:  I noticed some leaves “browning and yellowing, maybe dying” on my Paul Robeson tomato (see photo), do you have any suggestions?

MGCC Help Desk Response:  Thank you for contacting the UC Master Gardener Program Help Desk. It's been a busy season for the Help Desk, and we apologize for our delay in responding to your inquiry!

We understand that you are concerned about your Paul Robeson heirloom tomato plant's yellowing and dying leaves. The photo of your plant that you provided does not indicate a reason for concern for us. Overall, the plant looks healthy. It is not unusual for tomato plants to have browning leaves (especially lower leaves which may now be shaded from the sun) as we are headed toward the end of the growing season and have experienced some extremely hot weather recently. 

We do have a few suggestions on how to extend your plant's production and growing season by giving it the best cultural care you can:

• You can lightly fertilize and be careful to consistently but not over water.
      › After plants have set fruit you may want to fertilize with more nitrogen every 4 to 6 weeks.
      › Water plants when the soil dries in the top 2-3”. Tomatoes need regular irrigation during the growing season
• You may want to trim off the browning leaves as they won't be adding to the tomato's growth or production and could improve the plant's appearance.
• We notice that you have black weed cloth on the ground near your tomato plant. We suggest removing that cloth as it may be contributing to more heat in the soil. Instead use 2–3” of a wood or straw mulch around the plant instead of the cloth to block weed growth and keep the soil cooler. Be sure not to place the mulch against the plant stems.

We hope these suggestions help extend your tomato's production and growing season! Please let us know if you have any additional concerns or questions.

Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (http://ucanr.edu/blogs/CCMGBlog/).