Rooted in Research: A Guide to Successful Gardening the San Antonio Area

In this podcast what does the science say about core aerating the lawn, the concerns about "weed and feed" products, should leaves be raked or left alone, and finally the "how behind the why" of gardening on the Edward's Plateau on the northwest-north side of Bexar County and the sandy clay-pan soil on the southside of Bexar County.

Pilot Knob Austin

https://texashillcountry.com/pilot-knob-largest-extinct-volcano-remaining-in-central-texas/

Fort Inge

https://www.tshaonline.org/handbook/entries/fort-inge

Soil Preparation

https://agrilifeextension.tamu.edu/library/gardening/soil-preparation/

Soil Testing

https://bexar-tx.tamu.edu/homehort/archives-of-weekly-articles-davids-plant-of-the-week/it-all-starts-with-soil/

Calcareous Soils

Calcareous soils are defined as soils that contain more than 15% calcium carbonate (CaCO3) and are commonly found in arid, semi-arid, humid, and semi-humid regions. 

Caliche Soil

a hardened layer in soil, common in arid regions, formed when calcium carbonate cements soil particles (sand, clay, silt) into a rock-like, often whitish-gray, material.

General Soil Map of Texas

https://maps.lib.utexas.edu/maps/texas/texas-general_soil_map-2008.pdf

Improving Landscape Soils

https://aggie-horticulture.tamu.edu/wp-content/uploads/sites/5/2010/10/soilimprovement.pdf

Tom Ewing- Texas Geologic History Quick Overview

https://www.youtube.com/watch?v=A1zGgOktFQ8&t=6s

Karen Gardner is an exceptional extension certified Master Gardener and she grows all of her vegetables from seed. In this podcast she will take you step by step on how to successfully grow vegetables from seed from selecting seed, baking potting medium "soil", watering, "ferti-gating", lighting, potting up and harvesting.

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Bexar County Master Gardeners (BCMG) Links:
Bexar County Master Gardner Website BCMG Gardening Question Helpline: 210-631-0400
Follow BCMG on FB
Research and Podcast Notes / Links to further research : Link: Timely Tips on Starting Seedlings at Home

Link: Common Seed Starting Mistakes and How to Avoid ThemLink: Media, Repotting & Containers

Link: Seed StartingLink: Saving Seed of Hybrid Varieties-Once Not Recommended; Now Encouraged

Karen Gardner’s Recommendations for Seed Starting
1. Buy seeds from a reputable source 2. Make your own potting mix

3. Bake your potting mix to remove pathogens

4. Sterilize your pots

5. Water from the bottom or spray bottle misting

6. “Fertigate”7. Use heat mats at temp ranges for starting seeds

8. Add lights 2” above plants

9. When big enough, pot the seedlings up to a larger size pot

Karen’s Custom Potting Soil Mix: • Coconut Croix • Peat Moss

• Vermiculite

Seed Start Vocabulary Words:

Cotyledon: A cotyledon is a "seed leaf," the first leaf-like structure to emerge from a germinating seed, providing initial nutrition and energy to the seedling before its true leaves develop, with plants classified as monocots (one cotyledon, like corn) or dicots (two cotyledons, like beans) based on their count, often serving as food storage or becoming photosynthetic to support early growth before withering away. 
True Leaves: True leaves are the second set of leaves to grow on a seedling, appearing after the initial cotyledons (seed leaves) and resembling the mature plant's leaves, signifying the plant can now photosynthesize and produce its own food, a key milestone for transplanting or fertilizing.
Treated Seeds: Treated seeds are seeds coated with protective substances like fungicides, insecticides, or biologicals to shield them from pests and diseases in the soil, enhancing germination and crop establishment, often with a bright color for warning, but require careful handling to avoid environmental contamination or accidental consumption, as they are a significant pesticide delivery method in agriculture. 
Untreated Seeds: Untreated seeds are seeds that have not been coated with any synthetic chemicals or biological agents for pest/disease protection. 
Pelleted Seeds: Pelleted seeds are tiny or irregularly shaped seeds coated in an inert material (like clay) to make them larger, round, uniform, and easier to handle, see, and plant.  
Hybrid Seeds: Hybrid seeds are created by cross-pollinating two distinct parent plants, combining their best traits (like high yield, disease resistance, or flavor) into a superior first-generation (F1) offspring, though seeds saved from them won't grow true to type. 

GMO Seeds: Plants whose DNA has been altered in a lab to add new traits, like pest or herbicide resistance, creating characteristics not possible through traditional breeding.

“Fertigate”: It's a portmanteau of "fertilizer" and "irrigation," essentially "watering and feeding plants at the same time". Combine fertilizing and irrigating by adding soluble fertilizers directly into the irrigation water, delivering nutrients efficiently to plant roots through drip, sprinkler, or surface systems, saving time and water while increasing nutrient uptake.

TX Gardening Educational Events:
Saturday, Jan 31, 2026 9am-12pm: Pruning Fruit Trees at Fanick Nursery
Radio: Saturday Mornings Lawn & Garden Show 6am-9am on WOAI (1200 News Radio AM) Call in: 210-737-1200 or 1-800-383-WOAI

Email Karen: [email protected]Email David: [email protected]
Follow on FB / Follow on IG
Podcast: Bugs By The Yard

Gardening in Bexar County has its challenges. In this podcast we'll take a look things a successful gardener will be doing and avoiding. In addition, a calendar of learning events for local gardeners will given, and finally, we'll "dig deeper" into the challenges of gardening in our clay soils.

This podcast is brought to you by the Bexar County Master Gardeners, Bill Swantner host.

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Bexar County Master Gardeners (BCMG) Links:
Bexar County Master Gardner Website BCMG Gardening Question Helpline: 210-631-0400
Follow BCMG on FB
Research and Podcast Notes / Links to further research : Link: Historical temperature and rainfall data in San Antonio historically - National Weather Service

Link: Pruning: Basic Timing Advice for Trees, Shrubs, Perennials & VinesLink: International Society of Arboriculture’s “Find an Arborist” Page for the City of San Antonio

Link: International Society of Arboriculture’s Texas Chapter “Find an Arborist” 

Oak Wilt: 

Link: Preventing Oak Wilt: TX A&M Bexar Co Extension Education ArticleLink: Texas Oak Wilt Management - Texas A&M Forest Service

Garden Planning in January: Link: Dr. Steve George - Earth Kind Gardening 

TX Gardening Educational Events:
Friday, Jan 9, 2026 12-1pm: Rodeo Tomato Presentation at SABOT
Saturday, Jan 31, 2026 9am-12pm: Pruning Fruit Trees at Fanick Nursery
Radio: Saturday Mornings Lawn & Garden Show 6am-9am on WOAI (1200 News Radio AM) Call in: 210-737-1200 or 1-800-383-WOAI

Email Karen: [email protected]Email David: [email protected]
Follow on FB / Follow on IG
Podcast: Bugs By The Yard
Soil Information:
Link: General Soil Map of TexasLink: 4 Kinds of Soil in Bexar County Link: It All Starts with the Soil Link: Improving Clay SoilLink: Straight Talk about Iron Deficiency and Plants
Test your Soil PH & Nutrients with Texas A&M
Link: Order your Soil Testing KitLink: Soil Testing Paper Form - Texas A&M Lab
EDDHA - Chelated Iron - The iron supplement needed for San Antonio’s High PH Soils
Vegetable Planting Guide SA in January:
Link: Recommended Vegetable Varieties for Spring Planting
• Asparagus crowns: UC 157, Jersey Giant
• Cabbage Transplant: Golden Acre: (red) Ruby Ball and Red Acre: (hybrids) Rio Verde, Market Prize, Green Boy, Stonehead, Cheers
• Onion Transplants: Bulbing: Granex (yellow and white), Grano, Granex, Texas A&M 1015 Y; Texas A&M Supersweet: Red Burgandy, Crystal Wax; Green Scallions: Crystal Wax White Bunching
• English Peas: Wando, Little Marvel
• Pod Peas: (Grow on supporting structure) Sugar Snap, Sugar Daddy, Snappy, Sugar Mel
• Radishes: Champion, Cherry Belle, Early Scarlet Globe; Winter: Black Spanish, White Chinese
• Spinach Transplants: New Zealand, Malabar (Basella alba)
• Tomato Seeds
• Turnip Seeds: Purple Top White Globe, Just Right, Royal Globe, Tokyo Cross; Greens Feb 1 – Mat 20: All Top, Tyfon, Seven Top
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