Wednesday, May 20, 2009

A Bit Nippy?

I heard a familiar sound Tuesday morning, May 19, at about daybreak… someone scraping frost off of a windshield. I pulled up the covers and went back to sleep. My tomatoes and blooming strawberries were also nestled under warm blankets, protected from the cold. Later, I read my min/max thermometer and saw that the overnight low was 30 degrees… enough to kill bloom and flatten tender vegetable plants. My farming friends confirmed that it was below freezing. They protected acres of tender plants with row covers or sprinkler irrigation. Areas west of here reached 23 degrees by some accounts. Wow!

Row covers are a great way to get a few degrees of frost protection. Most garden catalogs sell them now. They are very light weight blankets made of spun-bonded polypropylene. Got my tomatoes thru the night and protected blooming strawberries from crop failure. Easy to apply and last for years. Add a wire hoop and you have mini greenhouse. Pictures above show a farm field with a more advanced version of row covers as well as the lightweight version in a garden bed.

Was this late frost the nasty side of Mother Nature? Maybe…its but not unexpected. Official records tell us that frosts have occurred throughout Bucks County until the last week in May. May 13 is the “frost-free” date for southern Bucks and May 28 in Northern Bucks. “Frost-free” means that after this date, 90 % of the time, there will be no further temperature below freezing. So, in fact, some of us have to sweat it out for another week, given the 1 in 10 chance of frost. But the weather woman says we’ll be OK. Summer temperatures are predicted for the rest of the month. Some folks use Mother’s Day as the green light to plant tomatoes another tender crops and that is a good guideline… but I always check the 10 day forecast about Mothers’ Day and plant accordingly.

And frost is not the whole story. Tomatoes do not thrive when night temperatures are in the low forties or colder. Peppers and eggplant are even more cold sensitive. And those folks seeding cukes, zukes and melons before June 1 are asking for trouble. There is a difference between surviving and thriving.

Want to get a jump on the growing season with the cukes, zukes and melons? Start seeds in peat pots or other small containers NOW. Plant in 10-14 days. You’ll have healthy plants with a leaf or two and minimal window-space disruption. In fact, start the plants on top of the fridge or any other spot that provides bottom heat. Move to light as soon as they germinate. Plant about June 1. Then watch out for cucumber beetles. Nobody said gardening was easy… they just said it was fun and interesting.

Monday, May 11, 2009

A fungus among us

Cedar apple rust is is full bloom. OK not bloom; it is shedding spores from its "telial horns" if you want to get technical about it. Folks brought lots of samples into the Extension office last week.

If you look at our native Eastern Red Cedar, (which is actually a juniper, Juniperus virginiana)you'll see these nifty orange, gelatinous masses of fungal tissue. The warm, wet weather we had recently was ideal for them to burst into maturity. The spores that are released from these slimy galls are carried in the air to the alternate host for the disease... apple. In fact there are several related rusts which affect hawthorn and quince as well. The deciduous, alternate host (apple, etc) will develop bright orange spots on leaves later this spring and fruit on these plants may become rusty, russeted and malformed.

So, cedar-apple rust and it's relatives are very interesting plant diseases. Two unrelated plants sharing a disease. And for most of us, that's all there is to it.. an interesting disease. It sometimes causes damage to Junipers in landscape settings; unless you are growing apples to eat, the leaf spots it causes are not a big deal. Backyard fruit producers have a couple of options. Spray fungicides (last week would have been perfect) or grow apple varieties that are resistant to this disease. There are crabapple varieties that are resistant, too.

No, there are worse fungi among I. Apple scab, anthracnose, powdery mildew.... spores of all of these diseases are thicker than pollen in our current atmosphere. Their signs of infection will be showing up soon. Stay tuned for pictures and horror stories from the world of plant disease.