Tuesday, February 9, 2010

complications in the greenhouse - live and learn

The UA Arboretum greenhouses are full of life and fresh air. A greenhouse prevents sudden temperature change, providing seeds a head-start in their development and prolonging the growing season for a farmer, increasing the potential crop yield.

On Sunday, a group of students entered the Arboretum greenhouse to discover that a mouse had maneuvered his way into a tray of unsuspecting beets and eaten every last seedling! So, students reseeded that tray and secured it with two plexiglass sheets on top so that mice and rats cannot lift off the covers to feast on the tender shoots. The garden was too wet to do anything with the soil, but students harvested handfuls of salad greens and kohlrabi. When the ground is soaking wet, it is not wise to garden because soil compacts tightly when wet. Soil compaction means that the little air bubbles that occur naturally in good soil structure are destroyed. It is very difficult, if not impossible, for plant roots to penetrate compacted soil in order to receive the nutrients, air and water they need. Plants grow best in a well composted, spongy-like soil with adequate moisture, sunlight and air.

It rained early this morning, but students carpooled to the Arboretum at 9:30 am.
Another discovery in the greehouse. A tray of lettuce greens got “damp off” – which is a fungus that rots the base of the plant at the root, causing the little seedlings to simply keel over and die, even though the stems and leaves look perfectly healthy. Damp off will live in warm, still, and dark spaces, so the way to minimize risk is to allow plenty of air circulation, expose the seedlings to sunlight, and take them off of the heating pad immediately after germination to allow them to cool off in the greenhouse. Students left the seedlings on the heating pad with a protective cover on them for longer than necessary, resulting in “leggy” plants that look as though they are reaching for sunlight and cool air. It is important to monitor germinating seeds every day in order to be sensitive to their growth process and responsive to their needs.
As an extra precaution against mouse visitations, Mary Joe Modica, Director of the Arboretum, placed a mouse cage with peanut butter in it by the germinating table. We’ll see if it lures in any seed snatchers.

Matthew Bush, Natural Resources Management major, weighs down the seed tray cover with a glass sheet, preventing rodents from lifting off the cover to eat seeds.

As a safe but effective precaution against ants, students spread a thin layer of diatomaceous earth around the germination trays. Diatomaceous earth is a naturally occurring sedimentary rock that can be crushed up into a white powder. It’s structure is rough and abrasive, so ants avoid climbing on it, as it will cut them and hurt them.
As a safe but effective precaution against damp off, students milled some long fiber sphagnum moss to sprinkle over the germinating trays. This moss has an acidifying effect in its surroundings by taking up cations and releasing hydrogen ions. Damp off, the fungal infection, does not take well to these acidic conditions. We will also prevent damp off simply by removing the trays from the heat as soon as they germinate, giving them adequate air circulation, and taking care not to over-water (roots grow into air pockets in the soil, but when there is excessive moisture in the soil, it takes up all of the air pockets and the roots have no where to grow, resulting in root rot).

The new garden plan will include a 4 foot wide pathway making an “x” cross The new garden plan will include a 4 foot wide pathway making an “x” cross design through the middle of the garden for easy bed access and optimal space utility.


Joe Brown said...

cat = integrated pest management...

Nicole Alexandra Ortega said...

good idea, but cat=no more birds at the arboretum. Mary Joe won't have it.