Tuesday, May 20, 2014

Another reason for water walls and row covers

The water tubes keep tomatoes warm through
 the sudden drop in temperature
It's been challenging gardening in Denver, Colorado this May. Early in the month it was 85 degrees F on May 4. Then we had snow and a 28 degree F low on May 11. Back to a 84 degree F high on May 18. Today, May 20, it was a hailstorm (see photos).

Kale and mesclun are cool season vegetables
 but this is too much. Brrr!
Thank goodness for growing in Wall O' Waters that provide the tomato transplants some hail protection. I expect plants to bounce back quickly, much faster than tomatoes growing in the open that are now sticks.

The greens under row cover fabric had a little protection and will regrow after their "trimming". It is definitely time to replace the fabric though.

Some gardeners go to the trouble to erect a frame with shade cloth fabric as a hail screen. In our variable climate, it can be a good idea.

Photo credit: Tomato in Wall O' Water after hail, Kale and Mesclun mix under row cover fabric post hail - both Carl Wilson

Monday, May 12, 2014

Fruit bud damage after the storm

May 12, 2014 snow on cherry fruit buds
Cold damage to plants is often much greater the day following a storm. This is when skies clear and without a cloud blanket to hold heat in, radiational cooling comes into play. At high Front Range Colorado elevations with low humidity, plant cold damage from this type of cooling is common.

At this stage of tree fruit bud development (full bloom to petal fall), we can expect 10 percent bud kill at 28 degrees F and 90 percent bud kill at 25 degrees F. This is with a 30 minute exposure and it doesn't matter if it is apples, cherries or peaches. European plums are somewhat hardier and it will have to go down to 23 degrees F to reach an expected 90 percent fruit bud kill and similarly to 24 degrees F for pears.

Cold damage to developing buds of fruit trees can be minimized by planting near the tops of slopes where cold air drains to lower levels and by avoiding blockages (such as fences) to cold air draining away .

Good yields of tree fruit may only be achieved in 2 or 3 years out of five on Colorado's Front Range. This is looking like it could be one of those off years.

Photo credit: Cherry fruit buds in May 12, 2014 snow - Carl Wilson

Friday, May 9, 2014

Greens weather returns

Winds and unseasonably warm Front Range Colorado weather (85 degrees F on May 4) may have been discouraging to those growing spring greens. If you had them protected and growing under a row cover fabric "dome", you gained several advantages. They were encased in a slightly higher humidity environment, shielded from the worst of the winds and recent heavy raindrops (and in some places hail), and protected from rabbits and other marauders.

Now that we're back to cooler weather (more seasonable 60 to 70 degrees F highs), early planted greens are maturing rapidly. It's time for cut and come again harvesting. Shear 2 inches above the soil line so they will regrow providing another harvest.

Another benefit to growing greens under row covers is that soil doesn't tend to be splashed up on the leaves because rain and irrigation droplets are cushioned and filtered through the spunbonded fabric. Less soil on leaves makes washing them a snap. The tempered row cover environment also enhances quality - so tender!

Meanwhile this upcoming Mother's Day weekend highs in the mid 40's F and lows around freezing with predictions for a rain/snow mix augur poorly for those who have already planted warm season vegetables. If you have tomatoes and peppers snug in water walls, no problem. Cool season vegetables will of course be right at home in this upcoming cold/snowy weather.

Photo credit: Mesclun filling row cover, Cut and come again harvesting of mesclun greens - both Carl Wilson