Still Useful to Plant in Wall O' Waters

Denver is receiving more sun and temperatures have warmed this week. That doesn't mean that it is ideal weather for planting tomatoes and other warm season vegetable transplants. Nighttime temperatures are still falling into the forties, far below the 50 F (and better yet 55 F) degrees nighttime temperature requirement for tomatoes. Note that the vine crops (squash, melons, pumpkins, etc. require 60 F degree nights).

A week after water channels filled at 
setup of Wall O' Water, sun has warmed water
sufficiently for planting within WOW cone. 
Plant deep for rooting along stem of this leggy 
tomato transplant.

So what's a gardener to do? You may have raised tomatoes from seed on your windowsill or purchased at a plant sale and the transplants are getting leggy. This is where Wall O' Waters come to the rescue. Even though often thought of for use in planting in the garden in April, they are still useful now.

Unlike mid-May when cloudy skies provided little solar radiation for heating the water in the tube walls of the Wall O' Waters, we are now receiving more sunlight. This provides warmth at night offsetting still cold night temperatures. Planting in Wall O' Waters also provides protection from wind and a sheltered environment for recovery from transplant shock.

Another benefit is protection from hail until plants grow above the walls. Even then plants pruned to the top of the Wall O' Waters by hail will retain enough undamaged plant within the Wall O' Waters to regrow.

If warm season transplants are planted in the open now without protection, they recover from transplant shock slowly and become stunted. We are assuming that night temperatures remain above freezing. They will require a week or more to recover from cold night stunting even when night temperatures warm above 50 to 55 degrees F in June. Although plants are leggy, you may be better off keeping them in pots and bringing them indoors at night until night temperatures warm if you aren't using Wall O' Waters.

See the manufacturer's website for more information on Wall O' Waters. Look to purchase them at your favorite local garden center.

Photo credit: Leggy tomato transplant for planting in Wall O' Water - Carl Wilson

Cool, Wet Weather Persists

Freeze damage on tender grape leaves

The limp grape leaves in the photo show one effect of cool, rainy spring weather. Clearing skies on May 10 as a storm system moved out after a week of rain allowed temperatures to plunge below freezing overnight damaging tender new leaf growth. Reserve buds will need to grow to take the place of the lost leaf tissue. Leaves that had already fully expanded and hardened were not damaged.

If you are anxious to plant warm season plants this is a lesson in hardening them off first. Plants purchased at plant sales should be shuttled in and out of the house or coldframe for at least a week, out on warm days and in overnight or on cold days. Nighttime temperatures remain in the forties at mid-month, way too cold for tomatoes and the like. Soil preparation including fertilization and adding compost are good places to direct your efforts now.

Spreading compost on vegetable
garden to mix in 4 to 6 inches

Soil temperatures at 4 inches have crept up to 54 degrees F after plunging to 50 degrees F following a week of cloudy, rainy weather. Keep in mind that the minimum soil temperature for tomatoes is 50 degrees F. Planting is possible under Walls of Water that keep above-ground plant parts warm overnight. Better yet use them in combination with plastic mulch that also utilizes the sun to warm soil for roots to grow. The plastic can be removed in June along with the Walls of Water if you care to not leave in place for the season.

 For some vegetable gardeners warm season crops are the reason to grow a vegetable garden. Cool, rainy spring weather has made this more of a cool season vegetable gardener's year so far.

Delayed planting of warm season vegetables to closer the end of the month is likely a better approach for those not using Walls of Water and plastic mulch. For information on planting warm and cool season vegetables, see the CSU Extension "Vegetable Planting Guide."

Photo credit: Freeze damaged grape leaves, Compost application - both credit Carl Wilson

Warm Season Vegetable Transplanting and Plant Sale Recommendation

This past week we saw a week of rain ending with snow that dropped 3.3 inches of precipitation in my Denver garden. The wet week ended May 10th with an overnight low of 31 degrees F.

Two years in a row! Tomatoes in Wall
O'Waters on May 12, 2014.

Any early-transplanted warm season vegetables required protection with Walls O'Water or second best the use of frost blankets. Even so warm season vegetables will likely be set back and take time to resume growth. Cloudy weather during the week didn't allow much solar gain for Walls O'Water.

Planting thoughts this week should take into account wet soils. Give them time to dry to a medium moisture content before transplanting or seeding. Don't walk in or work soil when wet; you will only destroy soil structure if you do. Meanwhile, consider what warm season vegetable varieties you want to plant this year.

Vegetable transplants being grown
by Denver Master Gardeners for their
May 16 and 17, 2015 sale.

I'm impressed with the wide selection of vegetable varieties offered by CSU Extension Denver Master Gardeners at their spring plant sale this coming weekend. The sale is Saturday, May 16 from 8am to 3pm and Sunday the 17th from 10am to 3pm.

Location is the Denver CSU Extension office in Harvard Gulch Park, 888 E. Iliff Ave, Denver, CO. This plant sale promises to be worth a visit and proceeds benefit CSU Denver's education programs.

Click to download and then open this file for more information and a list of varieties offered at the sale: Denver CMG Spring Plant Sale.