Math isn’t always fun! Here is Euclid explaining math in Raphael’s The School of Athens. Credit: Creative Commons.
There are a lot of things gardeners need to know to cultivate a beautiful landscape. Between plant zones, scientific names, soil chemistry, and pest identification, being a gardener takes curiosity and willingness to learn new things. Unfortunately, one topic that needs to be well understood, especially when it comes to applying pesticides and fertilizers, is a subject that many cringe when they hear it – mathematics!
Some of the most common mathematical concepts to have a good grasp on for gardening include area, converting decimals to percentages and vice versa, estimating volume and converting units, and determining how much fertilizer to be applied based on your fertilizer grade.
Here’s a couple tips to help you gardeners out with math.
Area
Most often, we need to know the square footage of our gardens. Rectangles are straightforward, you multiply length (in feet) by width (in feet) to get feet squared. Since most yards are not rectangles, we sometimes need to use other shapes to best calculate the area, such as circles and/or triangles. The area (A) of a circle is , where “π” is 3.14 and “r” is the radius (half of the diameter or the distance from the center to the edge). Remember that the little raised 2 means you multiply the radius by itself twice, not by two.
Most of the time, square feet is the best area unit to use. But just in case you need to know, one acre equals 43,560 square feet. So, if you find your lawn is 10,000 square feet, that means you have 0.23 of an acre (10,000/43,560).
Get your calculator’s out! Credit: iStockphoto.
Percent Conversions
This one may be better understood by most, but this becomes important later when we determine fertilizer needed or doing volume conversions. Basically, any percent can be divided by 100 to convert it to a decimal that can be used easily in other calculations. For example, 15% is the same as 0.15 (15/100). The easy way to remember is that 100% is the same as one, and 50% is the same as 0.5.
Volume Estimation and Conversions
Determining volume is required when figuring out how much mulch is needed for a garden bed or soil required for a raised bed. Converting one unit to another is especially important when determining how much pesticide product is needed to prepare a mixture.
For mulch and soil, the cubic feet (cf) or cubic yards (cy) are needed to figure out how many bags or truckloads will be needed. Most bulk products are sold by the cubic yard. Since we are dealing with volume, we need three measurements, the length, width, and depth. If we want to add three inches of mulch to a 500 square foot garden, we multiply the 500 by 0.25 feet (3”/12” equals 0.25 inches) to get 125 cubic feet. That is about 62 bags of mulch from the hardware store, which are often sold in 2 cubic foot bags. If we divide 125 cubic feet by 27 (three feet in a yard so 3’ x 3’ x 3’ = 27) we now have the answer in cubic yards and find that we need about 4.5 cubic yards of mulch. One cubic yard is roughly a half of a full-size pickup truck bed.
When it comes to converting liquid volume units to help with pesticide mixtures, fortunately we have the internet to help. However, it is a good idea to at least be familiar with converting ounces to gallons and vice versa. Since 128 ounces equals 1 gallon, to go from gallons to ounces you multiply by 128. For example, 0.5 gallons equals 64 ounces (0.5 x 128). To go from ounces to gallons, we just divide by 128. For example, 192 ounces equals 1.5 gallons (192/128).
Applying the proper amount of fertilizer keeps your landscape healthier and protects local waterbodies. Credit: UF/IFAS.
Calculating Fertilizer Needed
Okay, bear with me, as we are about to do some hard math and piece together several of the above concepts. First of all, most fertilizer rates are provided by extension resources and given in terms of pounds of a particular nutrient for a set area, usually 1,000 square feet. For example, when using slow-release fertilizer a homeowner should apply no more than one pound of nitrogen for every 1,000 square feet of lawn. To figure out how much actual fertilizer to apply to meet the recommendation, we will need 1) the recommended rate, 2) the size of the lawn, and 3) the fertilizer grade on the product (the three numbers that represent the percent N, P, and K). Our rate is one pound nitrogen per 1,000 square feet. The size of our lawn is 50 feet by 30 feet, so 1,500 square feet. We are going to use a 16-0-8 fertilizer. Now, here is the hard part! To figure out how much of our 16% nitrogen fertilizer will provide one pound of nitrogen, we need to convert 16% to a decimal (16/100 = 0.16) and then divide the amount of fertilizer we need by that number – 1 pound/0.16 – to find that 6.25 pounds of our fertilizer product are required for each 1,000 square feet. Since we have 1,500 square feet, we need to multiply our answer by 1.5, which gives us a total of 9.4 pounds.
Math is hard and there are usually many methods to get the same solution. When using pesticides and fertilizers in the home landscape, it’s important to make sure we’re using the right amount of materials to minimize the chance of harming ourself, our plants, and the local environment. If you need help, or would like someone to check your work, contact your local extension office.
Summer should be the time to relax and enjoy the fruit of all the hard work performed in the landscape over the previous winter and spring. However, there are still some essential tasks that need to be completed during the summer. Perform them in short energy bursts early in the morning or late in the evening.
1. Aerate Your Lawn
If your yard is starting to look weak and thin, even with fertilizing and proper moisture, it may need aeration. Aeration, which is creating channels into your lawn, allows water and nutrients to reach the deep roots of your grass more efficiently.
To test if you need to aerate your lawn, shovel up a patch of grass to a depth of at least four inches. If the layer of thatch is a half-inch thick or higher, your yard would benefit from aeration. There are self-drive aeration machines and tractor-pulled devices you can rent to make quick work of large areas. For smaller areas, simply punching multiple holes with a pitchfork will do the job.
2. Fertilize
Commercial landscape fertilizer applicators must obtain state certification.
Turf grass often displays a yellow color during the mid-summer rainy seasons due to the heavy rains flushing nitrogen away from plant roots. If your lawn is looking sad and yellow, chelated iron can often give a temporary green-up. Iron is not a replacement for nitrogen, but it can work well during our summer rainy season.
If you soil test revealed a potassium or magnesium deficiency, summer is a good time to make the last corrective application. Potassium (K) is an essential macronutrient. Fertilizer bags typically show the percentage of potassium in a product as the third number displayed on the front of the bag (e.g., the “8” in 16-2-8). Potassium acts as a “vitamin” for turf grass, increasing root strength, disease resistance and cold hardiness.
Magnesium (Mg), also a macronutrient, is essential for the production of chlorophyll, necessary for photosynthesis, and also plays a part in the movement of carbohydrates from leaves to other parts of the plant.
3. Don’t Mow Too Short
It’s a natural inclination to want to mow your grass as short as you can, so you have the longest time until you have to mow it again. However, giving your grass a buzz cut every time you mow can hurt your lawn over time.
While some turf grasses can be mowed relatively short, like Bermudas and some Zoysias, most grass types shouldn’t be cut shorter than two-and-one-half to four inches high. Mowing shorter than that can damage the growth point and leave it susceptible to disease and pest infestation. It can also dehydrate the grass and lead to long term damage.
5. Water Infrequently but Deeply
One common mistake made by many is watering too often and too shallow. When only given frequent shallow waterings, grass will begin to grow their roots upwards to take advantage of the small amounts of water, which makes weak and unhealthy. The grass becomes even more dependent on water and very susceptible to disease and insect attack.
Try watering only once or twice a week, but for a considerably longer time so that the water can penetrate deeper into the soil and encourage downward roots. Ideally, each irrigation zone is calibrated to determine the length of time it take to deliver ½ – ¾ inch. Then set the system to run every 3-4 days for that number of minutes. While checking the irrigation delivery system, make sure the rain shut-off device is working and set to the same ½ – ¾ inch.
6. Prevent Mosquitoes
Summer rains on a nearly daily basis lead to lots of standing water. In less than one inch of water, hundreds of mosquitoes can hatch 3 -5 days later. Not only are these blood-sucking pests annoying, but they can also transmit dangerous diseases like West Nile and Zika Virus. Even without disease, their bites are painful and irritating.
To prevent mosquitoes, make sure no standing water is allowed to remain in your yard, either in low points or in empty containers like flower pots or wheelbarrows. Any amount of stagnant water is the perfect breeding ground for mosquitoes. Take a walk around the yard, dumping out water and disturbing the oak and magnolia leaves that are acting a collection cup. Treat birdbaths and water features with floating “donuts” specifically designed to kill mosquito eggs.
While getting tasks done in quick morning trips to the yard, make sure to keep hydrated. Heat exhaustion can happen fast.
One of the major recent movements in production agriculture has been the widespread adoption of cover crops. This practice gives farmers a host of benefits, from erosion prevention to nutrient retention and recycling. However, using cover crops isn’t just for large scale farming operations. Hobby vegetable gardeners can absolutely employ similar systems on a smaller scale to reap the same benefits. For the past two years, I’ve used Buckwheat to provide a soil building cover during the heat of summer between spring and fall gardens. This winter, after my fall greens garden succumbed to frost, I decided to employ the same tactic with a mix of Red Clover (Trifolium pratense), White Clover (Trifolium Repens), and Crimson Clover (Trifolium incarnatum) to enhance my soil during the coldest months until spring tomato planting arrives!
Clover mix used as a cool season cover crop in raised beds. Photo courtesy Daniel Leonard.
While there are many different species of plants (rye, oats, wheat, various brassicas, etc.) that can be planted in November or December as cool season covers to deliver benefits like winter weed suppression, enhance soil organic matter, retain and harvest leftover nutrients, and provide habitat for beneficial insects, I chose Clover for an additional reason. In addition to the above benefits, Clover is a legume and also fixes atmospheric nitrogen, making it available for subsequent plantings! Not only is Clover an excellent soil cover, but it also provides some nitrogen fertilizer to the following vegetable garden!
Growing Clover, while not quite as simple as Buckwheat or small grain covers like oats and rye, is relatively easy for most gardeners. The first step is selecting which clover species and/or variety to grow. I chose a mix of Crimson, White, and Red Clover simply because I had several pounds of each left over from a previous field planting. However, any one of the three may be used by themselves or in various combinations. All are excellent choices for garden cover crops and have similar growing requirements. Crimson Clover is the most readily available, but all three species can be found at most farm and garden supply stores.
The next step is to prep your garden beds for clover seeding. I thoroughly remove weeds from my raised beds, lightly till the top couple of inches of soil, and rake to provide a level surface. Since clover seed is tiny, a smooth, clean seedbed is a must for excellent germination. Once this is done, your next should determine how much seed to plant. Recommended clover seeding rates are usually given on a per acre basis and range from 3-4 lbs/acre (White Clover) to 20-25 lbs/acre (Crimson Clover). Given these seeding rates, planting in a 4’x8’ (32 ft2) raised bed is only going to require a miniscule amount of seed.
Clover mix used as a cool season cover crop in raised beds. Photo courtesy of Daniel Leonard.
To ensure a good stand while minimizing risk of overplanting, I mix equal parts clover seed and either sand, vermiculite, or other media similar in size to clover seed and hand scatter over the surface of my beds, making sure to uniformly cover the entire bed. If you think the stand is too thick, you can always hand-thin after emergence.
As a group, clovers prefer moist soil that is not allowed to dry out completely. This isn’t usually a problem given the Panhandle’s frequent rainy cold fronts in winter, but if rainfall is inconsistent, some irrigation will be required. Supplemental fertilizer isn’t normally necessary when planting a clover cover in vegetable gardens because nutrients remaining from the previous veggie crops are usually sufficient for growth and development (N especially is not needed as legumes produce their own through N fixation). 2-3 weeks before you’re ready to plant your spring veggies, chop the clover cover into the top few inches of your bed to terminate it and release its nutrients back into the garden. It’s that easy!
Planting a winter legume cover crop like clover is a great way to harness the benefits of cover crops for your spring veggies and enhance the aesthetics of your otherwise barren and drab garden beds! For more information about growing winter cover crops or any other horticultural topic, contact your local UF/IFAS County Extension office. Happy Gardening!
Our trees and vines are flowering and lawns are starting to green up naturally, but one glance at the calendar and it is still early spring. The last official frost date for the Florida panhandle can be into April depending on location. We know our day time and night time temperatures are still fluctuating every other day. We also know the stores and nurseries are stocked with shelves and pallets of fertilizer. So the big question is when can I fertilizer my lawn?
Overseeded ryegrass on a centipedegrass lawn.
My answer after years of practice is always it depends, but my non-scientific rule of thumb to homeowners is wait until you mow three weeks in a row and make sure you’re past the last frost dates for your area. If you need to mow three weeks in a row for height, then your lawn is actively growing and most likely we are into a temperature range good for fertilizer applications. If you apply fertilizer to a lawn that is dormant, the fertilizer will not be taken up by your roots and it can leach below the root zone wasting money while not improving the lawn and possibly causing environmental concerns.
With that said, there are some factors to consider. We always recommend doing a soil test first. This can be done in advance of spring. Your test results might indicate having sufficient nutrients in the soil, so not applying would save you money and the lawn would still look good. The soil test will also indicate what nutrients are in excess or lacking, then you can apply only the nutrients needed.
I have found that fertilizer is still very much misunderstood. When I ask homeowners whether they consider fertilizer to be medicine or a stressor, most will answer medicine and we all know if a little medicine is good, then a bit more is better. However, it is more accurate to think of fertilizer as a chemical stressor. If my lawn is unhealthy, then I force my lawn to grow and it can further weaken my plants. Think of it like this, if you’re not feeling well at night before you go to bed, should you consume one of those big energy drinks? Not if you want to sleep and hopefully feel better in the morning. Apply fertilizer when the lawn is ready and capable of having a positive response when spring fully arrives.
Wakulla County Extension office mixed species turf.
Here are some items you should know before you fertilize the lawn. Fertilizers used in Florida should have a license number that begins with F followed by a series of numbers. It is important to check your fertilizers before you apply. You need to know what type of turfgrass you have in your lawn. We have a lot of bahiagrass and centipedegrass lawns in the panhandle. Each will require a different regiment. You are only allowed to apply one pound of nitrogen per 1,000 square feet per application and you should never apply more than the recommended rate. I always refer to a childhood fable “The Tortoise and the Hare” when thinking about plant health. Slow and steady makes for a better lawn in the long run. This means you need to measure your lawn, understand how to calculate the nitrogen and then apply correctly with the right equipment and spreader patterns. We also recommend very little phosphorus (the middle number on the fertilizer bag 15-0-15) for Florida lawns. Our soils are usually sufficient and this is another item your soil test results will confirm.
Remember, your local Extension office is always here to help especially making sure you treat the lawn right. Think before you apply because your long-term goal is improving the lawn quality.
The Florida Fertilizer Label (https://edis.ifas.ufl.edu/ss170) and General Recommendations for Fertilization of Turfgrasses on Florida Soils (https://edis.ifas.ufl.edu/lh014). T. W. Shaddox, assistant professor; UF/IFAS Fort Lauderdale Research and Education Center, Ft. Lauderdale, FL 33314
Homeowner Best Management Practices for the Home Lawn (https://edis.ifas.ufl.edu/ep236). Laurie E. Trenholm, professor, Extension turfgrass specialist, Environmental Horticulture Department; UF/IFAS Extension, Gainesville, FL 32611.
Bahiagrass for Florida Lawns (https://edis.ifas.ufl.edu/lh006). L. E. Trenholm, professor, turfgrass specialist, Department of Environmental Horticulture; J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; and J. L. Cisar, retired professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.
Centipedegrass for Florida Lawns (https://edis.ifas.ufl.edu/lh009). J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; L. E. Trenholm, associate professor, turfgrass specialist, Environmental Horticulture Department; and J. L. Cisar, professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.
Who doesn’t like strawberries, right? Backyard gardeners grow these low-growing herbs throughout the state and there is a significant commercial industry too, as Florida’s climate is ideal for cool season production.
Strawberries like well-drained sandy soils, so they’re a perfect fit for many areas in the Panhandle. Strawberries should be planted in the months of October or November as the plants are quite cold hardy. Shorter days and temperatures between 50°F and 80°F are ideal for fruit development.
Photo Credit: Cristina Carriz, UF/IFAS
Strawberries are also very versatile. You can plant them in the ground, in raised beds or even containers. Transplants should be planted 12” to 18” apart, with 12” row spacing. For best results, use a rich soil balanced with compost and sandy soil and both fertilize and water regularly. Mixing in 2 ½ pounds of 10-10-10 fertilizer into a 10’ x 10’ bed space should be sufficient to start. A sprinkle of fertilizer applied monthly throughout the growing season should also help ensure a solid yield.
Berry production begins to ramp up roughly 90 days after planting, but plants will continue to produce throughout the spring. When the weather gets warmer, the plants start to expend energy into producing runners instead of fruit. These runners will be new fruit producing plants for next season.
Transplants can be purchased from most garden centers. There are many varieties on the market, but “Florida-Friendly” cultivars include “Sweet Charlie”, “Camarosa”, “Chandler”, “Oso Grande”, “Selva”, and “Festival”. “Camarosa” has proven to be the most productive variety in North Florida. Any of these varieties are capable of producing two pints of fruit per plant.
As stated earlier, Florida has a significant strawberry industry and UF/IFAS has a supporting role. The UF/IFAS Gulf Coast Research and Education Center (GCREC) is home to the Strawberry Breeding Program. Cultivars are developed by traditional means, for the Florida commercial industry on an 11,000+ acres research site. Appearance, shelf life, sweet flavor and disease resistance are just some of the areas of selected breading research that is conducted on site. There is also a white strawberry soon to be released!
Photo Credit: Cristina Carriz, UF/IFAS
For more information, contact your local county extension office.
