Monday, March 10, 2014

Get Cool with Warm Soil



The vegetable cool-crop planting season is just around the corner.  Technically the dates are either two or four weeks from the last frost date (middle of May or so).  Hardy vegetables like peas, lettuce, spinach, arugula, onions and cole crops can be seeded or transplanted April 15 to May 15.  Semi-hardy veggies like beets, potatoes, carrots and Swiss chard can be planted from May 1 to May 15. But there’s no need to worry about following those time lines if you warm the soil now and use tunnels or cloches over the seed bed or transplants to keep them from continuous frosty nights below 40 degrees. 


I covered one of my raised beds today with black plastic and will keep it covered for 10 to 14 days.  If we get a long warm spell then I’ll take the soil temperature and if it’s 40 to 45 degrees, I’ll be seeding lettuce before noon that day!  Before putting down the plastic I started out by removing the heavy layer of chopped up leaves (read my mulch blogs from January about winter mulch).  I simply moved the leaves next door to my garlic planted raised beds.  They seemed happy to have the extra layer of protection and garlic doesn’t skip a beat with more mulch, those sturdy bulbs are pushing top growth already and they emerge right through anything.   
 
Black Plastic to Warm Raised Beds


After moving the mulch I made sure the ground was moist before covering with the plastic.  With recent storms, the beds were fine, if they had been dry, watering first helps create some humidity and heat below the plastic. I’ll keep you posted on my soil warming temperatures and seed planting. Below is a seeding and transplanting chart I put together for vegetable classes I teach in the Denver area. Everything is all relative to weather conditions so make sure your plan includes covering new seedlings or transplants. 


Vegetable Planting Calendar for the Colorado Front Range
Add at least 2 weeks for higher altitudes
For early planting (using Tunnels, Cloches, Cold Frames), move up all dates accordingly

 
 
CROP
COOL
SEASON
DAYS
TO
MATURITY
START SEEDS INDOORS
PLANT SEEDS IN THE GROUND
PLANT
TRANSPLANTS
OUTSIDE
FALL
SEED
Arugula
30

April 15-June 1

Mid-Aug
Asparagus
Perennial


Plant root crowns
April 15 to May 15

Beets
60-65

May 1-May 15

Mid-July
Broccoli
70
March 1-Mar15

April 1-May 15
Mid-July
Brussels Sprouts
80-95
March 1-Mar15

April 1-May 15
Mid-July
Cabbage
60-70
March 1-Mar15

April 1-May 15
Mid-July
Carrots
65-70

May 1-May 15

Mid-July
Cauliflower
50-55
March 1-Mar15

April 1-May 15
Mid-July
Cilantro
55-65
March 1-Mar30
May 1- May 15
May 1 -  May 15
Mid-July
Chard-Swiss
50

April 15-June 15

Mid-July
Celery
85-110


Fall planted best
Mid-July
Chives Onion
Perennial


May 15-June 15

Chives Garlic
Perennial


May 15-June 15

Garlic



Use Planting Bulbs
Mid-Sept
Mid-Oct
Horseradish
Perennial


May 15-June 15

Kale, Collards, Mustard Greens
50-55

April15-May15

Mid-August
Kohlrabi
55

April 15-May15

Mid-
August
Lettuce Leaf
40-45

April 15-May15

Mid-Aug
Lettuce Head
70-80

April 15-May15


Onion Bulb
100

April 15-May15


Onion Bunching
60-80

April 15-May15

Mid-July
Parsley
75
March 1-Mar30
May 1-May 15
May 1 – May 15
Mid-July
Parsnips
85-120

April 15-May15


Peas
50-65

April 15-May15

Mid-July
Potato Tubers
80-120

April15-May15


Radishes
20-30

April 15-May15

Mid -Aug
Rhubarb
Perennial


May 1 –June 15

Rutabaga
90-95

Early August

Early Aug
Spinach
30-50

April 15-May15

Mid-Aug
Turnip
40-75

April 15-May15

Mid-Aug
Vegetable Planting Calendar for the Colorado Front Range
Add at least 2 weeks for higher altitudes
For early planting (using Tunnels, Cloches, Cold Frames), move up all dates accordingly

 
CROP
WARM
SEASON
DAYS
TO
MATURITY
START SEEDS INDOORS
PLANT SEEDS IN THE GROUND
PLANT
TRANSPLANTS
OUTSIDE
FALL
SEED
Basil
60-85
April 15-May 15
June 1-July 15
June 1 – July 15
July 1
Beans, Bush
45-50

May20-July  1

July 1
Beans, Pole
60-65

May 20-June 15


Corn, Sweet
65-80

May 20-June 15


Cucumber
Slicing
48-72

May 20-June 15


Cucumber
Pickling
58-58

May 20-July 1


Eggplant
60-80
March 15-
April 10

May 20-June 10

Cantaloupe
85-120
April 15-May1
May 20-June 10
May 20-June 10

Okra
55-65
April 15-20
June 1-June 20
June 1-June 20

New  Zealand
Spinach
50-60

May 20-June 20


Pepper
70-80
March 1-
April 10

May 20-June 10

Pumpkin
95-110
April 15-May 1
May 20-June 5
May 20-June 5

Squash
Summer
55-65
April 15-May 1
May 20-June 10
May 20-June 10

Squash
Winter
55-105
April 15-May 1
May 20-June 10
May 20-June 10

Tomato
60-85
March 15-
April 10

May 20-June 10

Tomatillos
75-100
March 15-
April 10

May 20-June 10

Watermelon
75-100
April 5-15

May 20-June 10

































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