Posts Tagged ‘cabbage’

Worm Free Cabbage Crops? Check out Neem Oil

Monday, August 6th, 2012


I’ve done battle with the caterpillars of the small white and yellow cabbage butterflies for as long as I’ve gardened. The most destructive caterpillar, known as the Imported Cabbage Worm, is from a white butterfly native to Europe called the Cabbage White Butterfly (Pieris rapae).  These insects have only been in North America since the 1860’s, but they like it a lot on this side of the ocean and are a truly destructive pest.

The small green caterpillars of this butterfly will decimate unprotected cole crops.  Their presence is very easy to see.  They eat huge holes in the leaves of the brasiccas, they like to burrow into the center core of cabbages, and they leave trails and piles of frass wherever they occur.

A lot of gardeners use BT (Bacillus thuringiensis) as an organic control.  BT is widely used but I’ve left it alone mainly because of issues relating to its use in genetic engineering and several other possible problems, an overview of which you can read about here:

My best success has been using floating row covers of agricultural fabric.  The row covers have some problems, however.  The fabric tears easily and the moths find their way into and under the covers through the holes and any edges that might not be secured closely to the ground.  The covers are a pain to maintain and keep in place.  And it gets quite a bit hotter and more humid under the row covers than in the open air.  Brassicas prefer it cooler and drier.

Neem Oil

Then we found neem.  I’d heard about neem oil over the years.  Three years ago at a Garden Writers Conference in Oklahoma City, Geoff and I attended a presentation where the origins and insecticidal properties of this natural product were explained in depth.  And two years ago, at the MOSES Organic Farming Conference in La Crosse, Wisconsin, Geoff met Usha Rao of The Ahimsa Alternative,  and we obtained a supply of neem oil to test in our own gardens.

Neem oil is a vegetable oil pressed out of the fruit and seeds of the neem tree, Azadirachta indica, a fast growing tree of the mahogany family that is farmed in India, Pakistan, and Bangladesh, as well as throughout a lot of Africa.  All parts of the tree have useful properties and many people in India regard the tree as sacred.  Within the oil is an active ingredient Azadirachtin, which disrupts the digestive and molting processes of insects that feed on leaves where the oil is present and they eventually die after ingesting the neem.

I’m using a mixture of one tablespoon neem oil, 3/4 tablespoon of liquid horticultural soap, and one tablespoon of seaweed extract in a gallon of water.   The seaweed is there to help the neem mix better with the water and stick better to the plant leaves.  And it also has its own beneficial properties in the foliar feeding of plants. After the initial spray, I spray after rains or after I have to water the plants.  I’m presuming rains and watering may wash away the neem’s effectiveness.  The solution needs be thoroughly mixed.  Concentrated neem oil can burn plant leaves, and the neem oil will coagulate in colder water.

Also, while generally the neem is safe in use around beneficial insects, you should not spray it directly on them, so avoid spraying it when insects are pollinating squash flowers, for example.


I am happy to report that the results appear to be excellent.  I’ve got uncovered brassicas of all types almost totally free of insect damage and I’m pretty sure I’ll get to harvest all without any major insect losses.  It’s interesting, because the butterflies are present, they lay their eggs, the eggs hatch, but then the life cycle ends soon after the caterpillars start feeding.

Neem is supposed to be an all-around useful insecticide, but I haven’t figured out how to make it truly work well on all my cucurbits.  It appears to be quite effective against squash bugs, but I lost several plants to vine borers, which I can understand, as the vine borer caterpillar is protected inside the stem of the plant.  The neem spray seemed to do  nothing to protect against early damage from cucumber beetles, which destroyed several melon and squash plants almost as soon as I transplanted the seedlings into the beds.

Neem seems to be a very useful approach to a lot of garden pests, however, and the upside is that it is very low in toxicity and potential environmental concerns.  I’m going to keep working with it.  If it only gave me good, worm-free cole crops, it would be well worth its cost.

Anticipating the Main Harvest

Tuesday, July 24th, 2012

Here Come the Tomatoes

With this year’s warm weather, we’ll be picking things from the garden a lot earlier than most years.  I’m often late getting things started, but I did a good job of getting the tomatoes, peppers, and cole crops into the ground before the end of May.  The early start coupled with the hot weather is giving us veggies in July that we normally don’t start harvesting until August.  All in all, it appears we will have a good harvest as we go into late summer and fall.

Hot Peppers

This small bed holds most of the hot peppers.  In the foreground are Serranos and behind them are cayennes and some various Asian hot peppers.  Judy likes to freeze Serrano peppers.  She should have plenty.  The cayennes are exceptionally large this year and the pepper plants, in general, are taller than what I usually get.

Sweet Peppers

In front of the asparagus is my second pepper bed.  The small plants in front are Poblanos.  They are loaded with fruit.  The rest of the bed contains various sweet peppers.  I have a lot of Nardellos, the American-Italian heirloom that we like a lot.  Those too are very heavy with peppers.  Behind and to the right of the peppers are two potato beds, one red and one yellow.  Both are doing well.  I’ve already snitched a few red ones.

Sweet Potatoes

The sweet potatoes are loving the heat.  I can’t see what’s going on down below the vines, but I’m hoping for the best.  I’ve been covering the vines with ag fabric to keep the deer from munching on them.  The deer love sweet potato leaves.

Sweet Corn

We ate our first sweet corn, yesterday,  I only have one bed this year.  Most years I get two beds planted.  I’m inter-planting the corn with two heirloom pole beans that have traditionally been grown using corn stalks for trellises.  One bean is called Turkey Craw, the other is Missouri Wonder.  The beans in the corn have a long way to go, but they look just fine.

Leeks, Pole Beans, Tomatoes, and Onions

Here is my main bean crop, with leeks in the bed to the left, tomatoes, tomatillos, and eggplants in the bed to the right of the beans, and onions to right of the tomatoes.  You can see another bed of tomatoes in the back right and in front of those are two blue barrel rings holding some fingerling potatoes which I just planted.  It’s my plan to keep adding soil to the rings as the potatoes grow to try to get a larger yield.  I haven’t done this before, so we’ll have to see if it works.

The pole beans in the front of the picture are trellised onto four tripods.  Behind them in the same bed are bush beans.  They are just flowering but I expect good production.  Last year we had a similar size set up that got somewhat eaten by deer and we still had a huge harvest.   I expect a lot more beans this year.  We are getting Japanese beetles in the beans, but I’m able to keep ahead of much damage by cleaning off the beetles using my funnel trap, which you can read about here.

Ripening Egg Plants

I went overboard with the eggplants, I just didn’t have the heart to cull out the nice seedling starts, so we have 16 eggplants.  I normally grow four to six.  They are looking great.  We’re trying to figure out the best way to freeze them – any suggestions?

Three Cabbages

Here are three good looking cabbages in one of two beds dedicated to cole crops.  The other bed is under ag fabric.  Most of this bed was used to grow kohlrabi and we’ve already harvested about half the planting.  Judy talks about using kohlrabi in her recipe post.  I’ve been spraying my coles with a neem oil, soap, and seaweed mixture and that seems to have really made a huge difference on damage from  cabbage moths.  The moth eggs hatch but the caterpillars die when they eat leaves  containing neem oil.  While the neem spray hasn’t done much for the squash it seems very effective in the coles.

Zucchini #2

Here is our second zucchini.  We picked the first, yesterday.  We’ll have lots, I’ve got five healthy plants.  The squash, melons, cukes, and zukes all got a late start.  While the zucchini are doing well I’m really having some major problems both with cucumber beetles and squash vine borers.  I’m definitely going to lose a few squash and melon plants.  I always tell people starting out in gardening to grow a lot of different stuff.  Some will always succeed and even if you lose an entire crop of one vegetable you’ll still have plenty of the others.

Mammoth Sunflowers

These Mammoth Sunflowers are already ten feet tall and they aren’t done growing.  Their stalks are like tree trunks.

Unfortunately, this could be a year without basic root crops.  No carrots or beets in the ground, yet.  It’s not too late for either for a fall crop if I can get to it, but in any case, we’ll get plenty from the garden, this year.