Knowledge To Grow – Seedling Damping Off

So you have selected the seeds, carefully planted them in their pots, watered them, kept them warm, watched them germinate and start their growing process and then, one by one, fall over, shrivel up and die.

This horticultural disease is called damping off.  It is caused by soil borne fungi and it can occur before or after the little seedlings sprout from the soil.

The first sign that damping off may have occurred is the failure of the plant to emerge from the soil.  If seeds are attacked before they germinate, they will become soft and then decay.  If seedlings are attacked after they emerge, the plants stem tissue at the soil line will begin to decay and weaken, then fall over and die.  Sometimes only the roots are affected.  The stunted plants may continue standing for a time, but will eventually wilt and die.

It is best not to use old seed which may be weak.  If you do use old seed, test a sample for its ability to germinate by sandwiching the seed between two warm, moist layers of paper towel.   Look for seeds that have been pre-treated with a fungicide.  If none is available, you can add an amount of fungicide, equal to two match heads, to the seed packet.  Close the packet, give it a shake, then plant.  Seeds and seedlings are more susceptible to damping off if the soil temperature is less than favorable or is kept too wet.  The optimal soil temperature is dependent upon the type of seed being grown but most germinate when the soil temperature is between 68 and 86 degrees.

Sanitation is important because spores of the organisms that cause damping off can survive in dust and planting medium that is left over in flats, pots and plug trays.  Seedling pots and trays should either be new or used ones should be disinfected with a bleach and water solution.  Tools and surfaces being worked on should also be disinfected before preparing pots/trays for seed planting.  Use an uncontaminated soilless growing mix.

I have a little DIY project for you.  I like to use the black plastic trays measuring 2 ½”x10 ½”x21” for seed starting.  They are rather flimsy and tend to break or tear when being lifted while full with plant plugs.  Using some scrap lumber I had saved for who knows what, I made a wooden tray that makes transporting my seedlings a snap.  Inside dimensions are 1 ¾”x11”x21 ½”.  I just cut 2end pieces using ¾” thick lumber 12”x1 ¾”, 2 side pieces 21 ½”x 1 ¾”and 3 bottom pieces 23”x1”.  Sandwich the side pieces between the end pieces to create a rectangle, then fasten the 3 bottom pieces to the bottom, spacing them evenly.  Easy peasy!

As always, Happy Gardening!!

More information about gardening and related subjects can be found online. The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.

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