Fertilization and plant nutrients are often a mystery for many newbie gardeners...and experienced gardener's alike. While I find soil biochemistry and nutrient analysis fascinating, I'll bet that my soil chemistry books would substitute for sleeping pills for most. I get so many questions about fertilization and plant nutrients, I thought I'd start a series of plant nutrient profiles in order of importance. Don't worry, you won't have to read a thesis; I'll keep it simple and break it down easy so you can take the info and run with it in your own garden.

The third nutrient in the series: Potassium (K)

What does Potassium do? Potassium promotes flowers and fruits. Potassium helps with the formation of flowers and fruit, but it's also necessary for toughening growth, resistance to pests and diseases and drought and cold tolerance. Potassium deficiency is usually a problem on light sandy soils and is indicated by brown scorching on the leaves and curling of leaf tips.

When do I use Potassium? You can apply Potassium, or Potash (water soluble form of Potassium) in small amounts throughout the growing season, especially to veggie gardens and fruit crops. It is commonly applied to gardens, lawns and orchards as part of a balanced fertilizer. Greensand is a good organic amendment that includes Potash.

So, to keep it simple: Potassium = Flowers, Fruits & Vigor

There seems to be a lot of confusion about using spent coffee grounds in the garden. You can use coffee grounds directly in the garden, but as with anything, moderation is key.

It's often stated that coffee grounds are acidic, and therefore good for acid loving plants like hydrangea and azalea. However, when coffee grounds are brewed they become close to neutral with a 6.5-6.8 pH; also, as coffee grounds decompose in the soil any acidity neutralizes...so the soil acidifying effects are nominal to non-existant. You'll see recommendations to add fresh spent coffee grounds directly to the soil around the plants. But how much? Typically, you never want to add more than about an inch worth of coffee grounds around base of the plant, to the drip line. Then gently work it into the top layer of the soil. Make sure these original coffee grounds are completely decomposed before you add any new grounds. Roses, hydrangeas, hollies, and azaleas are all good candidates for coffee ground amending, but you can use them for any plants in your garden.

So what do coffee grounds do exactly? Well, they are a source of Nitrogen. However, that doesn't mean that coffee grounds are an instant Nitrogen fertilizer. Rather, as they decompose and are broken down by microbes, Nitrogen will be released and available to plants. So it takes time. You should think of coffee grounds as more of a soil amendment, like compost, rather than a fertilizer.

Where coffee grounds really go to work is in the compost bin. If you've used the maximum recommended amount around your plants already, the leftovers should go into the compost. If you're not sure how to make compost, all you really need to do is balance your "greens" and "browns". The "greens" are your sources of Nitrogen. The "browns" are your sources of Carbon. So which category does coffee grounds fall into? GREEN! That's right; because it's a source of Nitrogen, you should consider coffee grounds a "green", even though they are brown. Other greens would be vegetable kitchen scraps, fresh green pulled weeks or fresh green grass clippings. Browns are made up of dried leaves, dried grass clippings, newspaper, wood ash, etc. To properly balance your compost, just mix a ratio of 1:3 of greens to browns, by volume. So for 1 bucket of "greens" add 3 buckets of "browns" to balance out the compost. This will ensure a proper balance of nutrient sources for the beneficial microbes that will break down the compost. Make sure your compost gets about a half day of direct sun and you keep it moist, about the consistency of a wrung out sponge. Turn your compost regularly to aerate it.

Now, go drink your coffee and stop throwing those grounds in the garbage can!

Fertilization and plant nutrients are often a mystery for many newbie gardeners...and experienced gardener's alike. While I find soil biochemistry and nutrient analysis fascinating, I'll bet that my soil chemistry books would substitute for sleeping pills for most. I get so many questions about fertilization and plant nutrients, I thought I'd start a series of plant nutrient profiles in order of importance.

The second in the series is: Phosphorus (P)

What does Phosphorus do? Phosphorus encourages strong root systems and tubers; but it also assists in overall general health and fruit production by converting the sun's energy and nutrients into usable plant food. A Phosphorus deficiency leads to stunted, sickly looking plants and a lower quality fruit or flower. Phosphorus deficiency is not a huge problem in the home garden, but it is key to food and agricultural production. Think of Phosporus as something you'll mostly need to add in the vegetable garden. In certain soils Phosphorus may be plentiful, but bound up by soil particles and unavailable to plants. This is common in our heavy clay soils in N. Texas.

Often you'll hear recommendations to add no Phosphorus to your soils because there is already an excess (the water-soluable form of Phosphorus can be a big environmental and water quality problem.) But again, while you may have high levels of Phosphorus in the soil, it may not be available to your plants. Phosphorus exists in both organic and inorganic forms in the soil. Adding organic matter and stimulating microbial life can aid in the natural availability of Phosphorus. Soil microbes break down Phosphorus from its organic form to the inoranic form that is taken up by plants.

When do I use Phosphorus? It's best to use fertilizers that include Phosphorus on new plantings to encourage healthy root development. You can also apply in fall to the landscape to encourage root development over the winter. Animal manures provide Phosphorus and stimulate microbial growth, so they can often be a good soil additive for your landscape and vegetable garden; and a more desireable substitute for highly concentrated synthetic forms of Phosphorus.

So, to keep it simple: Phosphorus = Roots & Tubers

Fertilization and plant nutrients are often a mystery for many newbie gardeners...and experienced gardener's alike. While I find soil biochemistry and nutrient analysis fascinating, I'll bet that my soil chemistry books would substitute for sleeping pills for most. I get so many questions about fertilization and plant nutrients, I thought I'd start a series of plant nutrient profiles in order of importance. Don't worry, you won't have to read a thesis; I'll keep it simple and break it down easy so you can take the info and run with it in your own garden.

The first in the series is of course: Nitrogen (N)

What does Nitrogen do? In basic terms, it promotes leafy green growth. Plants typically need a good amount of Nitrogen to thrive. Nitrogen is fast acting, promotes the growth of leaves and other vegetative green growth. A Nitrogen deficiency produces pale or yellow small leaves, weak growth and spindly shoots. Too much Nitrogen can stunt flowering.

So when do you need to add Nitrogen to your soil? At the beginning of the growing season in early spring, and then several late-spring and summer applications to turf grass and veggies. In warm climates you can also add Nitrogen to all plantings in early fall, but not too late: New leafy growth encouraged by Nitrogen is more suceptible to frost.

Nitrogen can be added in liquid form or granules. Liquid forms will be taken up by plants right away, so they are good to use if your plants are Nitrogen deficient. But they don't persist in the soil. For a slow release effect, use a granular form. Organic fertilizers typically top out at about 9% Nitrogen, but you can apply them regularly without fear of damaging your plants. Blood Meal is a good source of Nitrogen. Animal manures such as cow, turkey and chicken manure, will naturally provide about 18-22% Nitrogen so they are a great boost especially for veggie gardens; but they can burn plant roots if used fresh; compost manures for best use.

Legumes and Vetches, such as peas and fava beans, can fix atmospheric Nitrogen in the soil. They form a beneficial union nodes in their roots with soil bacteriain the genus Rhizobium, which help convert Nitrogen into a form useable by plants. Rotating legumes and vetches around your garden is a great way to provide free Nitrogen.

So, to keep it simple, Nitrogen = Green.

Lavender plants like dry hot conditions...so it may seem like a no-brainer that Lavender should perform very well in Texas, right? Well, not so...Here in North Texas, we have particularly heavy clay soil that doesn't drain well when wet. This is the kiss of death for most lavender plants. Many Lavender plants don't even make it through their first year planted before they succumb to exces moisture.

There are some varieties that perform better than others. I've had particularly good luck with this 'Goodwin Creek'. Of course, you should alway plant your Lavender "high and dry" meaning plant it in a higher spot in the garden, so it receives better drainage, and don't plant it where it will receive excess irrigation. Plants need to dry between waterings. You can topdress your plants with expanded shale to keep moisture away from the crown of the plant. Always plant in full sun. If you've struggled with growing Lavender in the garden, give it a try in containers.

Lavender is also a favorite of the bees...bonus!

An Unusual Spinach Substitute

For those of us that live in warm climates, we can't grow things like spinach and tomatoes at the same time....we actually have to split our edible growing seasons into "winter" and "summer". Spinach and other leafy greens thrive from fall through winter, but quickly bolt as our summer heat comes on. So how do you manage to keep in fresh leafy greens from the garden year round? Look for alternatives to the cool season greens; like Malabar Spinach.

This beautiful warm-season vine produces fleshy edible spinach-like leaves on purple stems all summer long. Now, it doesn't taste exactly like spinach, but that might be a bonus to some at it has a milder flavor. You can use it just the same as you would spinach; by cooking older leaves and using small young leaves in fresh salads. Not to mention, it's a beautiful ornamental. I grow mine on decorative trellises or other supports.

I don't know about you but I'm a big fan of "re-seeders". Those are crops that "come true" from seed and volunteer themselves all over the garden. Now, some re-seeders can be a nuisance, yes, but re-seeding edible crops come in quite handy. One of my favorite re-seeders is Dill.

My husband has asked me more than once..."so, why did you plant all this Dill again?" To which I always answer "I didn't, it planted itself". I suppose my front garden does contain what might seem to be a ridiculous number of Dill plants at this point, but they're just so pretty...and I happen to love Dill. There are of course other re-seeders in my garden, such as Arugula and Mexican Feather Grass. But none so prolific as the Dill. What are your favorite garden re-seeders?

As I get more questions about the new 'Black Diamond' Crapemyrtles and where to buy them, I thought I'd post this video about them from the LSU AgCenter.

Also, you can mail order plants from Plant Me Green and Sooner Plant Farm. Now, these are brand new plants, so do expect availability to be limited at this stage and don't expect to pay bargain prices!