Friday, April 22, 2011

Rain at last - more needed

The official Denver precipitation total is now up to 0.84 inches for April (still 0.45 below normal for the month though). People closer the foothills received more rain during the upslope weather late in the week. Seedlings are coming up below the poly germination blanket (photo left) even without added sprinkling. See how to use this germination aid in previous post.

The name of the game now is to keep moisture on and through your soil. This is particularly true if you have added compost or turned under a winter cover crop for soil improvement.

Remember that the melding of the organic matter into the soil relies on microorganisms and they aren't active unless there is sufficient moisture. Turned under winter cover crops like rye and Austrian winter pea need a month to break down before planting vegetables IF the soil is moist enough for the microorgaisms to work over the buried plants.

Compost will release nitrogen during the growing season in addition to improving the structure of the soil. Again, soil moisture is needed for this to happen.

Check not only surface moisture, but also subsurface moisture content. After a dry winter, initial rains may have only moistened the top few inches. You may have to add supplemental moisture to wet the soil throughout the soil "profile." How does your soil moisture look down 6 to 10 inches?

Photo credit: Germinated seedlings under blanket - Carl Wilson

Monday, April 11, 2011

Dry spring weather

Both low precipitation and frequent drying winds have dogged Front Range gardeners trying to germinate vegetable seeds this spring.

Many of the cool season vegetable seeds planted at the beginning of the season are small and can't be planted deep. These include broccoli, onions, lettuce, kale and radish. Being near the surface leaves them vulnerable to drying out during the days-to-germination period. If seeds start germination and then dry before emergence, they often perish.

What to do? In addition to frequent, light watering, the use of straw mulch or germination blankets can help. A useful germination blanket is spun polyester floating row cover fabric tacked down with wire U-pins. These fabrics gerenally allow 85% light transmission as well as passage of moisture through to the soil.

Blanket removal immediately upon seedling emergence is not mandatory and can be delayed until several true leaves have formed and seedlings are well established - that is if fabric is anchored loose enough to "float".

Photo credit: Floating row cover seed germination blanket, Carl Wilson