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

Hail - Nature's pruning

Widespread hailstorms and rain struck the Front Range Colorado area the evening of June 6 from south Denver to Parker and on south to Colorado Springs. Hail sizes ranged from rice grain to one inch sized and even higher. Copious amounts of rain accompanied the storms. In southwest Denver, my garden received 2 inches of rain and rice grain size hail.

The most important action the day after is to stand outside the garden for a post-event look. Check your raingauge and asses the size of the hailstones; pea-sized hail or less is generally not a big problem for plants. Avoid stepping into gardens because wet soil compacts easily. Turn off automatic irrigation systems. Then go away and wait for soil to dry out.

After a few days to a week, pick up detached branches and leaves. Damage to vegetables often looks worse than it really is. These plants are annuals and respond quickly to pruning. When soil dries and it's time to water again, use a low-strength liquid fertilizer to stimulate new growth. Vegetables that are newly established and reduced to sticks may have to be replaced while transplants are still available. It's also early enough to reseed many vegetables. The plants pictured here will recover nicely without replacement.

Patience and waiting for recovery and new growth are the best actions to take following hail events.

Photo credit:  Hail at base of raspberries with set fruit. Hail damage to summer squash and tomato. All credit Carl Wilson

Hail recovery hope

To encourage those with gardens struck by hail, this post features pictures from a previous year's hailstorm. While chances of recovery depend on the extent of the damage, plants can surprise. Fruiting vegetables always seem to sustain the worst damage, particularly the big-leafed vegetables like squash and pumpkins. Roots escape underground and regrow. Leafy vegetables generally come back.

These photos of tomatoes and straightneck summer squash are from a July 21 hailstorm. White hailstones are visible in tomato photo. Click on photos to see enlarged view.



The photos below show plants August 17, about a month later. The Yellow Taxi tomato is sparse and shows hail-nicked foliage but did ripen fruit. The summer squash put on an amazing amount of growth and more fruit.

Photo credit: All five photos in post - Carl Wilson

Hail NO!! - But for some unfortunately YES

June is always an unsettled weather month in between cool May and hot July. Hail has already been a worry for growers and some have already taken their licks. A June 8 storm nailed Ft. Collins and a short pelting got a vegetable project I'm working on in Denver on June 13.

Vegetables with broad leaves take it hard as evidenced by the broccoli photo right. Soil may also crust afterwards as seen in this photo from a clay soil northeast of Ft. Collins. With the heavy rains that frequently accompany hail, it is often best to stay off the soil until it dries out to avoid further compaction. There is little you can do at that point anyway. Once soil dries, cultivation to break up crusts may be helpful.

Hoops for low tunnels with floating row cover fabric at the ready may offer some protection if you're on the spot to pull up covers when hail threatens. If hail stones are large, fabric may be shredded and protection value likely decreases.

Patience is a virtue after a hail storm. Once it is time to water again, consider weak fertilizer in the water to add to the stimulus for new growth delivered by the hail pruning. If plants aren't responding after a few weeks, remember the possibility of early July seeding of the 50 to 60 day vegetables for fall harvest.

Vegetable plants are resilient following hail and growers can only imitate that quality.

Photo credit: Hail damage on broccoli, Soil crusting following hail, Low tunnels and row cover fabric - All Carl Wilson

Hail update and Early blight time

After the hail -
In my previous post about the July 20 hailstorm that hit the west Denver Metro area, I promised to report back to you. Here is the one month update.

Squash came back fantastically. The crooknecks sent two branches to either side and grew abundant new leaves (photo left). They also have been producing well (photo right). Compare to the photo published in the July 23 post. If the growing points aren’t completely destroyed, it’s obvious squash has a notable ability to bounce back.

The tomatoes are also on the rebound and maturing fruit especially the ‘Sweet Tangerine’ (see photo left). These annual vegetables have amazing resilience to plant-damaging hail events. Patience and water soluble fertilizer applications as discussed in the July 23 post can salvage a partially destroyed garden.

Early blight time -
Late summer is early blight disease time in the tomato plot. Infected leaves develop ½ inch, irregular brown target-like spots (photo below right - click photo to enlarge). As this fungal disease progresses, spots grow together causing lower leaves to yellow and drop. If severe enough, defoliation leads to fruit sunscald and decreased production. Warm temperatures, abundant rainfall, overhead irrigation, and high humidity promote disease development.

Fungal spores are splashed from overwintering plant debris and infected tomato family weeds such as horsenettle and nightshade. Volunteer tomato plants that sprouted from last years stray fruit left overwinter also can carryover the disease.

Manage the disease by eliminating volunteer tomatoes. Properly fertilize plants with nitrogen. Late season nitrogen deficiencies stress plants, making them more susceptible. Avoid working around tomatoes when leaves are wet. Brushing leaves can bruise them and the water aids spores in germinating and moving into leaf tissue. Irrigate at the base of plants rather than wetting leaves. Apply sulfur dust to protect uninfected foliage against infection. And finally, be sure to clean up garden debris thoroughly this fall.

While early blight can be manageable in late summer gardens and fruit can mature before frost, severe cases can limit production.

Appreciation is extended to Mary Small, Jefferson County CSU Extension Plant Clinician, for disease information.

[Photo credit Carl Wilson: Squash leaf recovery and squash fruiting 1 month after hail, ‘Sweet tangerine’ tomato fruit with white hail nicks visible on plants, early blight target spots and yellow leaves on tomato.]

Coping with hail damage

The hail storms that pounded the west Denver Metro area and Englewood early this week and later the Castle Rock area have prompted this post. Some landscapes took golf ball sized stones. My own garden received a 15 minute dose of marble sized hail leaving only the skeletons of tomatoes (click photo left to enlarge white hail stones and plant destruction details).

First, hail is generally accompanied by an ample amount of rain so stay out of the garden. Wet soil compacts easily and tramping on wet ground only worsens garden problems.
Another reason to stay out of the garden is that plants are more resilient than you may think. Don’t let the damage discourage you.

Most vegetables are annuals and respond to hail pruning with new growth. The limiting factor is the amount of growing season left to them before frost. Brittle plants such as peppers and large-leafed plants like squash (photo right) suffer the most. Leafy vegetables will re-grow and yield, root vegetables are protected underground and survive, and fruiting vegetables generally suffer the most.

Tomatoes tend to surprise in their ability to come back. My hope is that by hedging my bets through planting some shorter season Early Girl and cherry tomato types, I will still realize something where longer season heirloom types will probably not produce. The deep, extensive tomato root systems in my raised beds will help plants recover. I’ll keep you posted on this hope.

Once the water dries and its time to water again, I’ll begin using a weak fertilizer containing nitrate-type nitrogen in the water. Nitrate nitrogen signals plants to grow.

I will also continue sowing mid-summer vegetables for fall harvest as discussed in the July 2nd post. It’s not too late. Though I’m by nature accepting of hail events as a given in Colorado gardening, the act of planting does help soothe a gardener’s psyche. Doing something productive and once again seeing the wonder of germinating seeds is always energizing. Chins up intrepid Colorado gardeners!

Photo credit: Hail damaged tomatoes and Hail damaged crookneck squash, Carl Wilson