Vegetables and nutrients

I have such a hard time realizing how MUCH I need to fertilize vegetables, conditioned by the sparse habits of native plants and their parsimonious ways. 

I always think I add plenty of compost, and dig in composted manure, and add Espoma organic fertilizer, etc. etc., but in looking at Jim Wilson's excellent new vegetable gardening book, obviously I'm not producing anything close to spinach and lettuce with the size of the leaves shown in the photos. Vegetables are definitely nutrient and water hogs, being domesticated, to be sure.  And then I see that he recommends a 1/2 cup of organic fertilizer at the base of each transplant.  Yikes.  No wonder my vegetables are modest in size.

It'll be interesting to see how the tomatoes, peppers, and other vegetables do in the raised beds this summer in the mountains.  The 'soil' is essentially straight compost with additional composted manure.  I'll take a sample for a soil test this weekend and see what I have.  And I'll do the same for my Piedmont beds.

I think my leafy greens do well in flats because I've heavily amended the potting mix with organic fertilizer!

My guess is that in my home vegetable garden areas, the soil may have become somewhat depleted of nitrogen and other nutrients, since I haven't been adding lots of extra fertilizer (I do fertilize, but not a lot).  Adding mushroom compost,  composted cow manure, and homemade compost helps, but in our warmth and humidity, it decomposes quickly.

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Do my shrubs need fertilizer?

A participant in a perennial class today mentioned fertilizers. She'd found that the local Wal-Mart isn't selling 10-10-10 (NPK) anymore, only 10-0-10 (eliminating the phosphorus that can be problematic in streams, ponds, and lakes). She likes to apply 10-10-10 around her garden every spring, she said. Another participant said that she'd found 10-10-10 at Lowes.

And I'm thinking, goodness, why would you want to spread fertilizer around shrubs and trees in your garden every year?

Annuals and edibles certainly need fertilizer (I use organic time-release and compost), but most shrubs, and trees should be quite fine with regular organic mulches, since we don't harvest them. Some herbaceous perennials will benefit from a bit of (preferably organic) fertilizer in addition to mulch, since we often do cut their flowers or remove their spent foliage.

Soil tests provide the most accurate information, of course, about your soil nutrient levels and degraded urban and suburban soils may need building up, to be sure.

But the most important thing to do is to keep the organic matter produced by your garden plants (leaves, twigs, etc) IN your garden, recycling it as either as mulch, compost, or both. That's what happens in natural ecosystems, after all.

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Nutrients for vegetables

A question in a recent kitchen gardening program has had me thinking about nutrients and vegetables again. Vegetables are so much more nutrient-intensive than perennials, shrubs, trees, or any 'landscape' plants, it's hard to realize sometimes how much they appreciate excellent, fertile soil to grow in.

The person who asked the question wondered why her vegetables just seemed average, in their compost-enriched raised beds (but with no added fertilizer). Her soil test was 'fine' for vegetables, according to our state Ag Services Lab.

But another participant had just told us about her two Early Girl tomato plants last season that produced so many tomatoes that she was giving them away to her friends, neighbors, people at her church, etc. But she was fertilizing her plants.

Hmm. Most of my vegetable plants are a lot more in the average category - nice and productive, but nothing overwhelming. But I don't fertilize much either, after adding compost at each rotation or bed preparation. It's hard (as a plant ecologist) to get my head around nutrient and water hungry vegetables.

I think the key is that if you look at the advice for sustainable gardening using compost and green manures, it takes a LOT more than you'd ever think to keep soil nutrients high. 4-5 inches of compost is often recommended for additions to each year's bed -- that's a lot of compost!

And actually, now that I think about it, the Ag Services Lab recommendations are probably assuming that you'll add fertilizer (whether inorganic or organic) to your vegetables over the growing season.

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Composting is fun

My mom's house in Texas was nestled on a woody, juniper-filled hillside in a upscale neighborhood in NW Austin, only marginally "landscaped" above and below the house. The deck extended over a scruffy lawn (no sun, of course), so from the deck, it was easy to throw the odd banana peel or lettuce leaf into the scrubby forest.

She wasn't a gardener, so there was no need to create compost, but I think it appealed to her thrifty ways and sense of environmentalism. Her mother was a gardener, though, so maybe she had composted back when the vegetable garden was a source of food for a good bit of the winter, after canning. I still remember being impressed by the jars of canned beans and tomatoes in Grandma's cellar and the vegetable gardens and berry patches that she had when I was a child.

Even before I was a gardener, I enjoyed putting our vegetable and fruit scraps in a compost heap, being environmentally-inclined myself. We had established one within one of our shrub borders in our first house in Georgia, so we didn't have to toss vegetable scraps in the trash. When we moved to Clemson, our neighbor asked if he could have the compost -- "solid gold" of course, for those of us who want to add nutrients and organic matter to their gardens. We said, of course you can have the compost, but it certainly got me thinking more about it.

Here in SC, I set up a simple wire-bin compost system, and we started throwing more things into it-- all of our kitchen vegetable trimmings, but also the results of our weed-pulling efforts, spent vegetables from the garden, etc. It's now grown to a 3-bin system, especially after we moved in against the fence, post garden shed. I've also added a garage-can composter to hopefully 'cook' any weed seeds left in the compost, so have tried to ramp it up to being efficient.

Essentially, what we're doing is cold composting -- turning is somewhat of a chore in these bins, since they're surrounded by hay bales to prevent Mocha (our dog) from foraging for nasty spoiled bits, so it's a bit of a reach to "turn" the compost, as recommended by many 'experts.'

In one of my programs, a participant said that she blended up all of her compostable materials, eggshells included, to speed up composting. A lovely idea, if you have a spare blender and the initiative to do it. Do I need to admit that eggshell bits are part of the compost I spread on the vegetable garden?

But it's great to see that pail of compost go out almost every day, and see how small the trash bag is each week, since we also recycle everything we can! There are all sorts of attractive compost pails that coordinate with kitchen decor. This one is a Turkish copper pail from Gardeners Supply. Quite nice, and certainly a lot better than an open plastic container!

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Changing out vegetable beds for fall

After pulling out spent beans & tomatoes a few days ago, I started readying those spots for fall plants. I like to add more compost, a bit of organic fertilizer, and lime, depending on how each block looks (not very scientific or orderly), but some vegetables are more demanding than others, and almost all vegetables are much more fussy than the tough perennials, shrubs, and trees that we like to grow in our garden.

Spinach (along with beets and chard) prefer a much more neutral soil (almost 6.5-7.0) than ours tend to be here in the SE, so adding more lime is helpful, at least over the long run, although it would have been best to have added it some months ago! Pelletized lime is the easiest to use in the garden.

In fact, one of the harder things I've had to learn about vegetable-growing is that vegetables tend to be nutrient and water 'hogs' -- and have generally been selected to grow tasty fruits and leaves for us to consume, and take up plenty of nutrients and water in the process.

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