Question
Are there any tomato varieties that are resistant to late blight?  I've lost all my plants in mid-late summer for the past two years.  I live in Hendersonville, NC, mountain area, 2800 feet elevation where nights are cool and we've had a lot of rain the past two summers.  If no resistant varieties, is there something that can be applied to tomato plants to prevent blight or treat it once it's started?

Also, I've had terrible luck starting vegetables from seeds - damping off problem.  I'm not using grow lights and starting seeds in my basement.  What are the guidelines for preventing damping off and getting healthy plant starts?

One other question.... I like the look of pine straw mulch in flower beds but wonder if chemicals leached from pine needles is injurious to plants or inhibits their growth.

Answer
Despite the many varieties of hybrids that have been developed over the past few years, there are still none that are resistant to blight. I am attaching a site that posts a handy chart with all the different varieties and their resistance to diseases.

http://vegetablemdonline.ppath.cornell.edu/Tables/TomatoTable.html

Once this disease enters the soil, it must be killed off before you can plant tomatoes, peppers, or eggplant in that same area. Chemicals will not do the trick. One way to do so is with a method called solarization. By laying 3 mil black plastic over the entire area for a 3 month period, the heat will kill the disease. Unfortunately, this must be done in the warmer months meaning nothing can be grown there that season.

You will also need to rotate your crops on a 3 year cycle. This eliminates the disease from propagating. It also is beneficial for the plants since different plants tend to draw varying amounts of nutrients from the soil.

Finally, you must amend your soil every spring or fall with organic matter. These materials include aged manure, compost, and peat. The result will be a healthier soil with many microorganisms combating disease and pests.

In regard to mulching, I do not recommend pine needles because they are extremely acidic. Most plants need a neutral pH level of 7.0. Soils composted with pine needles often fall below 6.5. Most annuals and vegetables will do poorly at this level.

Damp-off is caused by one of three factors. These include contaminated soil, poor air circulation, or water-logged soil.

I always recommend purchasing sterilized starting medium for seedlings. You can buy this by the bag at most garden centers and nurseries. This combination of perlite, vermiculite, and peat moss is light and airy, therefore allowing the young seedlings to receive plenty of oxygen through their roots. But most importantly, it is sterile, virtually eliminating any chance of damping off.

Contamination can also be caused by unclean flats and/or pots. At the end of every growing season, if you choose to reuse the same flats next year, make sure you sterilize them in a solution of one tsp. of bleach per gallon of warm water.

The other possibility is a lack of air circulation. Many seed starters cover their flats with a plastic dome to retain moisture and aid germination. If using this procedure, it is very important to remove the cover once the first seed germinates. Otherwise, the lack of air can prove fatal to the young seedlings.

If you抮e not using a covering, you may need to improve the air circulation. You mentioned that you are running a fan. If so, make sure you keep it at least three feet away from the flats and keep the setting on low. The fan must rotate to keep the air moving.

Finally, do not over-water. Water-logged soil deprives the soil of oxygen and nutrients. Your flats and pots must have a drainage hole or else the process will fail.

In summary, let me give you some tips on growing plants from seed. This is my standard instructional document that I send to all new seed starters, so some of it may be redundant with what I have stated above.

Seedlings need to be in simulated sunshine for at least 14 hours per day. They also need 8 hours of dormancy for good growth. You either need to invest in fluorescent bulbs called gro-lights which are as close to natural light as anything sold on the market, or substitute these with less expensive bulbs. By using one cool and one warm white fluorescent in combination, you will achieve the same effect.

If given the correct conditions, namely adequate moisture, strong light, and healthy soil, the plants will germinate and grow to maturity with few or any problems. To maintain moisture, seeds should be covered with plastic. I grow my seedlings in seed trays with individual cell packs. After sowing, I cover with a pre-fitted plastic dome. But once the first seedlings sprout, it is important to remove the cover to avoid damping-off disease. This is a fatal fungus disease which only attacks young seedlings, and is caused by inadequate air circulation and non-sterile soil. That is why I advise all those who start seeds indoors to only use sterile, soiless mixes. These mixes can be purchased at any garden center.

Once the seedlings develop their second set of leaves, you can begin supplementing the plants with a diluted solution of fertilizer. Since you want to keep the nitrogen and salt levels low at this stage of growth, I highly recommend staying away from the chemical mixes. Rather, use a seaweed/fish emulsion formula at 1/4 the recommended level. This will help the plants?development and also help ward off disease. You can purchase these organic formulas at most garden centers or through online websites such as Gardens Alive.

I hope this answered your questions. Good luck, and have a great weekend.

Regards,

Mike